apache_beam.dataframe.io module¶
Sources and sinks for the Beam DataFrame API.
Sources¶
This module provides analogs for pandas read
methods, like
pandas.read_csv()
. However Beam sources like read_csv()
create a Beam PTransform
, and return a
DeferredDataFrame
or
DeferredSeries
representing the contents
of the referenced file(s) or data source.
The result of these methods must be applied to a Pipeline
object, for example:
df = p | beam.dataframe.io.read_csv(...)
Sinks¶
This module also defines analogs for pandas sink, or to
, methods that
generate a Beam PTransform
. Users should prefer calling
these operations from DeferredDataFrame
instances (for example with
DeferredDataFrame.to_csv
).
-
apache_beam.dataframe.io.
read_gbq
(table, dataset=None, project_id=None, use_bqstorage_api=False, **kwargs)[source]¶ This function reads data from a BigQuery table and produces a :class:`~apache_beam.dataframe.frames.DeferredDataFrame.
Parameters: - table (str) – Please specify a table. This can be done in the format ‘PROJECT:dataset.table’ if one would not wish to utilize the parameters below.
- dataset (str) – Please specify the dataset (can omit if table was specified as ‘PROJECT:dataset.table’).
- project_id (str) – Please specify the project ID (can omit if table was specified as ‘PROJECT:dataset.table’).
- use_bqstorage_api (bool) – If you would like to utilize the BigQuery Storage API in ReadFromBigQuery, please set this flag to true. Otherwise, please set flag to false or leave it unspecified.
-
apache_beam.dataframe.io.
read_csv
(path, *args, splittable=False, **kwargs)[source]¶ Read a comma-separated values (csv) file into DataFrame.
Also supports optionally iterating or breaking of the file into chunks.
Additional help can be found in the online docs for IO Tools.
Parameters: - filepath_or_buffer (str, path object or file-like object) –
Any valid string path is acceptable. The string could be a URL. Valid URL schemes include http, ftp, s3, gs, and file. For file URLs, a host is expected. A local file could be: file://localhost/path/to/table.csv.
If you want to pass in a path object, pandas accepts any
os.PathLike
.By file-like object, we refer to objects with a
read()
method, such as a file handle (e.g. via builtinopen
function) orStringIO
. - sep (str, default ',') – Delimiter to use. If sep is None, the C engine cannot automatically detect
the separator, but the Python parsing engine can, meaning the latter will
be used and automatically detect the separator by Python’s builtin sniffer
tool,
csv.Sniffer
. In addition, separators longer than 1 character and different from'\s+'
will be interpreted as regular expressions and will also force the use of the Python parsing engine. Note that regex delimiters are prone to ignoring quoted data. Regex example:'\r\t'
. - delimiter (str, default
None
) – Alias for sep. - header (int, list of int, None, default 'infer') – Row number(s) to use as the column names, and the start of the
data. Default behavior is to infer the column names: if no names
are passed the behavior is identical to
header=0
and column names are inferred from the first line of the file, if column names are passed explicitly then the behavior is identical toheader=None
. Explicitly passheader=0
to be able to replace existing names. The header can be a list of integers that specify row locations for a multi-index on the columns e.g. [0,1,3]. Intervening rows that are not specified will be skipped (e.g. 2 in this example is skipped). Note that this parameter ignores commented lines and empty lines ifskip_blank_lines=True
, soheader=0
denotes the first line of data rather than the first line of the file. - names (array-like, optional) – List of column names to use. If the file contains a header row,
then you should explicitly pass
header=0
to override the column names. Duplicates in this list are not allowed. - index_col (int, str, sequence of int / str, or False, optional, default
None
) –Column(s) to use as the row labels of the
DeferredDataFrame
, either given as string name or column index. If a sequence of int / str is given, a MultiIndex is used.Note:
index_col=False
can be used to force pandas to not use the first column as the index, e.g. when you have a malformed file with delimiters at the end of each line. - usecols (list-like or callable, optional) –
Return a subset of the columns. If list-like, all elements must either be positional (i.e. integer indices into the document columns) or strings that correspond to column names provided either by the user in names or inferred from the document header row(s). If
names
are given, the document header row(s) are not taken into account. For example, a valid list-like usecols parameter would be[0, 1, 2]
or['foo', 'bar', 'baz']
. Element order is ignored, sousecols=[0, 1]
is the same as[1, 0]
. To instantiate a DeferredDataFrame fromdata
with element order preserved usepd.read_csv(data, usecols=['foo', 'bar'])[['foo', 'bar']]
for columns in['foo', 'bar']
order orpd.read_csv(data, usecols=['foo', 'bar'])[['bar', 'foo']]
for['bar', 'foo']
order.If callable, the callable function will be evaluated against the column names, returning names where the callable function evaluates to True. An example of a valid callable argument would be
lambda x: x.upper() in ['AAA', 'BBB', 'DDD']
. Using this parameter results in much faster parsing time and lower memory usage. - squeeze (bool, default False) –
If the parsed data only contains one column then return a DeferredSeries.
Deprecated since version 1.4.0: Append
.squeeze("columns")
to the call toread_csv
to squeeze the data. - prefix (str, optional) –
Prefix to add to column numbers when no header, e.g. ‘X’ for X0, X1, …
Deprecated since version 1.4.0: Use a list comprehension on the DeferredDataFrame’s columns after calling
read_csv
. - mangle_dupe_cols (bool, default True) –
Duplicate columns will be specified as ‘X’, ‘X.1’, …’X.N’, rather than ‘X’…’X’. Passing in False will cause data to be overwritten if there are duplicate names in the columns.
Deprecated since version 1.5.0: Not implemented, and a new argument to specify the pattern for the names of duplicated columns will be added instead
- dtype (Type name or dict of column -> type, optional) –
Data type for data or columns. E.g. {‘a’: np.float64, ‘b’: np.int32, ‘c’: ‘Int64’} Use str or object together with suitable na_values settings to preserve and not interpret dtype. If converters are specified, they will be applied INSTEAD of dtype conversion.
New in version 1.5.0: Support for defaultdict was added. Specify a defaultdict as input where the default determines the dtype of the columns which are not explicitly listed.
- engine ({'c', 'python', 'pyarrow'}, optional) –
Parser engine to use. The C and pyarrow engines are faster, while the python engine is currently more feature-complete. Multithreading is currently only supported by the pyarrow engine.
New in version 1.4.0: The “pyarrow” engine was added as an experimental engine, and some features are unsupported, or may not work correctly, with this engine.
- converters (dict, optional) – Dict of functions for converting values in certain columns. Keys can either be integers or column labels.
- true_values (list, optional) – Values to consider as True.
- false_values (list, optional) – Values to consider as False.
- skipinitialspace (bool, default False) – Skip spaces after delimiter.
- skiprows (list-like, int or callable, optional) –
Line numbers to skip (0-indexed) or number of lines to skip (int) at the start of the file.
If callable, the callable function will be evaluated against the row indices, returning True if the row should be skipped and False otherwise. An example of a valid callable argument would be
lambda x: x in [0, 2]
. - skipfooter (int, default 0) – Number of lines at bottom of file to skip (Unsupported with engine=’c’).
- nrows (int, optional) – Number of rows of file to read. Useful for reading pieces of large files.
- na_values (scalar, str, list-like, or dict, optional) – Additional strings to recognize as NA/NaN. If dict passed, specific per-column NA values. By default the following values are interpreted as NaN: ‘’, ‘#N/A’, ‘#N/A N/A’, ‘#NA’, ‘-1.#IND’, ‘-1.#QNAN’, ‘-NaN’, ‘-nan’, ‘1.#IND’, ‘1.#QNAN’, ‘<NA>’, ‘N/A’, ‘NA’, ‘NULL’, ‘NaN’, ‘n/a’, ‘nan’, ‘null’.
- keep_default_na (bool, default True) –
Whether or not to include the default NaN values when parsing the data. Depending on whether na_values is passed in, the behavior is as follows:
- If keep_default_na is True, and na_values are specified, na_values is appended to the default NaN values used for parsing.
- If keep_default_na is True, and na_values are not specified, only the default NaN values are used for parsing.
- If keep_default_na is False, and na_values are specified, only the NaN values specified na_values are used for parsing.
- If keep_default_na is False, and na_values are not specified, no strings will be parsed as NaN.
Note that if na_filter is passed in as False, the keep_default_na and na_values parameters will be ignored.
- na_filter (bool, default True) – Detect missing value markers (empty strings and the value of na_values). In data without any NAs, passing na_filter=False can improve the performance of reading a large file.
- verbose (bool, default False) – Indicate number of NA values placed in non-numeric columns.
- skip_blank_lines (bool, default True) – If True, skip over blank lines rather than interpreting as NaN values.
- parse_dates (bool or list of int or names or list of lists or dict, default False) –
The behavior is as follows:
- boolean. If True -> try parsing the index.
- list of int or names. e.g. If [1, 2, 3] -> try parsing columns 1, 2, 3 each as a separate date column.
- list of lists. e.g. If [[1, 3]] -> combine columns 1 and 3 and parse as a single date column.
- dict, e.g. {‘foo’ : [1, 3]} -> parse columns 1, 3 as date and call result ‘foo’
If a column or index cannot be represented as an array of datetimes, say because of an unparsable value or a mixture of timezones, the column or index will be returned unaltered as an object data type. For non-standard datetime parsing, use
pd.to_datetime
afterpd.read_csv
. To parse an index or column with a mixture of timezones, specifydate_parser
to be a partially-appliedpandas.to_datetime()
withutc=True
. See Parsing a CSV with mixed timezones for more.Note: A fast-path exists for iso8601-formatted dates.
- infer_datetime_format (bool, default False) – If True and parse_dates is enabled, pandas will attempt to infer the format of the datetime strings in the columns, and if it can be inferred, switch to a faster method of parsing them. In some cases this can increase the parsing speed by 5-10x.
- keep_date_col (bool, default False) – If True and parse_dates specifies combining multiple columns then keep the original columns.
- date_parser (function, optional) – Function to use for converting a sequence of string columns to an array of
datetime instances. The default uses
dateutil.parser.parser
to do the conversion. Pandas will try to call date_parser in three different ways, advancing to the next if an exception occurs: 1) Pass one or more arrays (as defined by parse_dates) as arguments; 2) concatenate (row-wise) the string values from the columns defined by parse_dates into a single array and pass that; and 3) call date_parser once for each row using one or more strings (corresponding to the columns defined by parse_dates) as arguments. - dayfirst (bool, default False) – DD/MM format dates, international and European format.
- cache_dates (bool, default True) –
If True, use a cache of unique, converted dates to apply the datetime conversion. May produce significant speed-up when parsing duplicate date strings, especially ones with timezone offsets.
New in version 0.25.0.
- iterator (bool, default False) –
Return TextFileReader object for iteration or getting chunks with
get_chunk()
.Changed in version 1.2:
TextFileReader
is a context manager. - chunksize (int, optional) –
Return TextFileReader object for iteration. See the IO Tools docs for more information on
iterator
andchunksize
.Changed in version 1.2:
TextFileReader
is a context manager. - compression (str or dict, default 'infer') –
For on-the-fly decompression of on-disk data. If ‘infer’ and ‘filepath_or_buffer’ is path-like, then detect compression from the following extensions: ‘.gz’, ‘.bz2’, ‘.zip’, ‘.xz’, ‘.zst’, ‘.tar’, ‘.tar.gz’, ‘.tar.xz’ or ‘.tar.bz2’ (otherwise no compression). If using ‘zip’ or ‘tar’, the ZIP file must contain only one data file to be read in. Set to
None
for no decompression. Can also be a dict with key'method'
set to one of {'zip'
,'gzip'
,'bz2'
,'zstd'
,'tar'
} and other key-value pairs are forwarded tozipfile.ZipFile
,gzip.GzipFile
,bz2.BZ2File
,zstandard.ZstdDecompressor
ortarfile.TarFile
, respectively. As an example, the following could be passed for Zstandard decompression using a custom compression dictionary:compression={'method': 'zstd', 'dict_data': my_compression_dict}
.New in version 1.5.0: Added support for .tar files.
Changed in version 1.4.0: Zstandard support.
- thousands (str, optional) – Thousands separator.
- decimal (str, default '.') – Character to recognize as decimal point (e.g. use ‘,’ for European data).
- lineterminator (str (length 1), optional) – Character to break file into lines. Only valid with C parser.
- quotechar (str (length 1), optional) – The character used to denote the start and end of a quoted item. Quoted items can include the delimiter and it will be ignored.
- quoting (int or csv.QUOTE_* instance, default 0) – Control field quoting behavior per
csv.QUOTE_*
constants. Use one of QUOTE_MINIMAL (0), QUOTE_ALL (1), QUOTE_NONNUMERIC (2) or QUOTE_NONE (3). - doublequote (bool, default
True
) – When quotechar is specified and quoting is notQUOTE_NONE
, indicate whether or not to interpret two consecutive quotechar elements INSIDE a field as a singlequotechar
element. - escapechar (str (length 1), optional) – One-character string used to escape other characters.
- comment (str, optional) – Indicates remainder of line should not be parsed. If found at the beginning
of a line, the line will be ignored altogether. This parameter must be a
single character. Like empty lines (as long as
skip_blank_lines=True
), fully commented lines are ignored by the parameter header but not by skiprows. For example, ifcomment='#'
, parsing#empty\na,b,c\n1,2,3
withheader=0
will result in ‘a,b,c’ being treated as the header. - encoding (str, optional) –
Encoding to use for UTF when reading/writing (ex. ‘utf-8’). List of Python standard encodings .
Changed in version 1.2: When
encoding
isNone
,errors="replace"
is passed toopen()
. Otherwise,errors="strict"
is passed toopen()
. This behavior was previously only the case forengine="python"
.Changed in version 1.3.0:
encoding_errors
is a new argument.encoding
has no longer an influence on how encoding errors are handled. - encoding_errors (str, optional, default "strict") –
How encoding errors are treated. List of possible values .
New in version 1.3.0.
- dialect (str or csv.Dialect, optional) – If provided, this parameter will override values (default or not) for the following parameters: delimiter, doublequote, escapechar, skipinitialspace, quotechar, and quoting. If it is necessary to override values, a ParserWarning will be issued. See csv.Dialect documentation for more details.
- error_bad_lines (bool, optional, default
None
) –Lines with too many fields (e.g. a csv line with too many commas) will by default cause an exception to be raised, and no DeferredDataFrame will be returned. If False, then these “bad lines” will be dropped from the DeferredDataFrame that is returned.
Deprecated since version 1.3.0: The
on_bad_lines
parameter should be used instead to specify behavior upon encountering a bad line instead. - warn_bad_lines (bool, optional, default
None
) –If error_bad_lines is False, and warn_bad_lines is True, a warning for each “bad line” will be output.
Deprecated since version 1.3.0: The
on_bad_lines
parameter should be used instead to specify behavior upon encountering a bad line instead. - on_bad_lines ({'error', 'warn', 'skip'} or callable, default 'error') –
Specifies what to do upon encountering a bad line (a line with too many fields). Allowed values are :
- ’error’, raise an Exception when a bad line is encountered.
- ’warn’, raise a warning when a bad line is encountered and skip that line.
- ’skip’, skip bad lines without raising or warning when they are encountered.
New in version 1.3.0.
-
New in version 1.4.0:
- callable, function with signature
(bad_line: list[str]) -> list[str] | None
that will process a single bad line.bad_line
is a list of strings split by thesep
. If the function returnsNone
, the bad line will be ignored. If the function returns a new list of strings with more elements than expected, aParserWarning
will be emitted while dropping extra elements. Only supported whenengine="python"
- delim_whitespace (bool, default False) – Specifies whether or not whitespace (e.g.
' '
or' '
) will be used as the sep. Equivalent to settingsep='\s+'
. If this option is set to True, nothing should be passed in for thedelimiter
parameter. - low_memory (bool, default True) – Internally process the file in chunks, resulting in lower memory use while parsing, but possibly mixed type inference. To ensure no mixed types either set False, or specify the type with the dtype parameter. Note that the entire file is read into a single DeferredDataFrame regardless, use the chunksize or iterator parameter to return the data in chunks. (Only valid with C parser).
- memory_map (bool, default False) – If a filepath is provided for filepath_or_buffer, map the file object directly onto memory and access the data directly from there. Using this option can improve performance because there is no longer any I/O overhead.
- float_precision (str, optional) –
Specifies which converter the C engine should use for floating-point values. The options are
None
or ‘high’ for the ordinary converter, ‘legacy’ for the original lower precision pandas converter, and ‘round_trip’ for the round-trip converter.Changed in version 1.2.
- storage_options (dict, optional) –
Extra options that make sense for a particular storage connection, e.g. host, port, username, password, etc. For HTTP(S) URLs the key-value pairs are forwarded to
urllib.request.Request
as header options. For other URLs (e.g. starting with “s3://”, and “gcs://”) the key-value pairs are forwarded tofsspec.open
. Please seefsspec
andurllib
for more details, and for more examples on storage options refer here.New in version 1.2.
Returns: A comma-separated values (csv) file is returned as two-dimensional data structure with labeled axes.
Return type: DeferredDataFrame or TextParser
Differences from pandas
If your files are large and records do not contain quoted newlines, you may pass the extra argument
splittable=True
to enable dynamic splitting for this read on newlines. Using this option for records that do contain quoted newlines may result in partial records and data corruption.See also
DeferredDataFrame.to_csv()
- Write DeferredDataFrame to a comma-separated values (csv) file.
read_csv()
- Read a comma-separated values (csv) file into DeferredDataFrame.
read_fwf()
- Read a table of fixed-width formatted lines into DeferredDataFrame.
Examples
NOTE: These examples are pulled directly from the pandas documentation for convenience. Usage of the Beam DataFrame API will look different because it is a deferred API. In addition, some arguments shown here may not be supported, see ‘Differences from pandas’ for details.
>>> pd.read_csv('data.csv')
- filepath_or_buffer (str, path object or file-like object) –
-
apache_beam.dataframe.io.
to_csv
(df, path, transform_label=None, *args, **kwargs)[source]¶ Write object to a comma-separated values (csv) file.
Parameters: - path_or_buf (str, path object, file-like object, or None, default None) –
String, path object (implementing os.PathLike[str]), or file-like object implementing a write() function. If None, the result is returned as a string. If a non-binary file object is passed, it should be opened with newline=’’, disabling universal newlines. If a binary file object is passed, mode might need to contain a ‘b’.
Changed in version 1.2.0: Support for binary file objects was introduced.
- sep (str, default ',') – String of length 1. Field delimiter for the output file.
- na_rep (str, default '') – Missing data representation.
- float_format (str, Callable, default None) – Format string for floating point numbers. If a Callable is given, it takes precedence over other numeric formatting parameters, like decimal.
- columns (sequence, optional) – Columns to write.
- header (bool or list of str, default True) – Write out the column names. If a list of strings is given it is assumed to be aliases for the column names.
- index (bool, default True) – Write row names (index).
- index_label (str or sequence, or False, default None) – Column label for index column(s) if desired. If None is given, and header and index are True, then the index names are used. A sequence should be given if the object uses MultiIndex. If False do not print fields for index names. Use index_label=False for easier importing in R.
- mode (str, default 'w') – Python write mode. The available write modes are the same as
open()
. - encoding (str, optional) – A string representing the encoding to use in the output file, defaults to ‘utf-8’. encoding is not supported if path_or_buf is a non-binary file object.
- compression (str or dict, default 'infer') –
For on-the-fly compression of the output data. If ‘infer’ and ‘path_or_buf’ is path-like, then detect compression from the following extensions: ‘.gz’, ‘.bz2’, ‘.zip’, ‘.xz’, ‘.zst’, ‘.tar’, ‘.tar.gz’, ‘.tar.xz’ or ‘.tar.bz2’ (otherwise no compression). Set to
None
for no compression. Can also be a dict with key'method'
set to one of {'zip'
,'gzip'
,'bz2'
,'zstd'
,'tar'
} and other key-value pairs are forwarded tozipfile.ZipFile
,gzip.GzipFile
,bz2.BZ2File
,zstandard.ZstdCompressor
ortarfile.TarFile
, respectively. As an example, the following could be passed for faster compression and to create a reproducible gzip archive:compression={'method': 'gzip', 'compresslevel': 1, 'mtime': 1}
.New in version 1.5.0: Added support for .tar files.
Changed in version 1.0.0: May now be a dict with key ‘method’ as compression mode and other entries as additional compression options if compression mode is ‘zip’.
Changed in version 1.1.0: Passing compression options as keys in dict is supported for compression modes ‘gzip’, ‘bz2’, ‘zstd’, and ‘zip’.
Changed in version 1.2.0: Compression is supported for binary file objects.
Changed in version 1.2.0: Previous versions forwarded dict entries for ‘gzip’ to gzip.open instead of gzip.GzipFile which prevented setting mtime.
- quoting (optional constant from csv module) – Defaults to csv.QUOTE_MINIMAL. If you have set a float_format then floats are converted to strings and thus csv.QUOTE_NONNUMERIC will treat them as non-numeric.
- quotechar (str, default '"') – String of length 1. Character used to quote fields.
- lineterminator (str, optional) –
The newline character or character sequence to use in the output file. Defaults to os.linesep, which depends on the OS in which this method is called (‘\n’ for linux, ‘\r\n’ for Windows, i.e.).
Changed in version 1.5.0: Previously was line_terminator, changed for consistency with read_csv and the standard library ‘csv’ module.
- chunksize (int or None) – Rows to write at a time.
- date_format (str, default None) – Format string for datetime objects.
- doublequote (bool, default True) – Control quoting of quotechar inside a field.
- escapechar (str, default None) – String of length 1. Character used to escape sep and quotechar when appropriate.
- decimal (str, default '.') – Character recognized as decimal separator. E.g. use ‘,’ for European data.
- errors (str, default 'strict') –
Specifies how encoding and decoding errors are to be handled. See the errors argument for
open()
for a full list of options.New in version 1.1.0.
- storage_options (dict, optional) –
Extra options that make sense for a particular storage connection, e.g. host, port, username, password, etc. For HTTP(S) URLs the key-value pairs are forwarded to
urllib.request.Request
as header options. For other URLs (e.g. starting with “s3://”, and “gcs://”) the key-value pairs are forwarded tofsspec.open
. Please seefsspec
andurllib
for more details, and for more examples on storage options refer here.New in version 1.2.0.
Returns: If path_or_buf is None, returns the resulting csv format as a string. Otherwise returns None.
Return type: Differences from pandas
This operation has no known divergences from the pandas API.
See also
read_csv()
- Load a CSV file into a DeferredDataFrame.
to_excel()
- Write DeferredDataFrame to an Excel file.
Examples
NOTE: These examples are pulled directly from the pandas documentation for convenience. Usage of the Beam DataFrame API will look different because it is a deferred API.
>>> df = pd.DataFrame({'name': ['Raphael', 'Donatello'], ... 'mask': ['red', 'purple'], ... 'weapon': ['sai', 'bo staff']}) >>> df.to_csv(index=False) 'name,mask,weapon\nRaphael,red,sai\nDonatello,purple,bo staff\n' Create 'out.zip' containing 'out.csv' >>> compression_opts = dict(method='zip', ... archive_name='out.csv') >>> df.to_csv('out.zip', index=False, ... compression=compression_opts) To write a csv file to a new folder or nested folder you will first need to create it using either Pathlib or os: >>> from pathlib import Path >>> filepath = Path('folder/subfolder/out.csv') >>> filepath.parent.mkdir(parents=True, exist_ok=True) >>> df.to_csv(filepath) >>> import os >>> os.makedirs('folder/subfolder', exist_ok=True) >>> df.to_csv('folder/subfolder/out.csv')
- path_or_buf (str, path object, file-like object, or None, default None) –
-
apache_beam.dataframe.io.
read_fwf
(path, *args, **kwargs)[source]¶ Read a table of fixed-width formatted lines into DataFrame.
Also supports optionally iterating or breaking of the file into chunks.
Additional help can be found in the online docs for IO Tools.
Parameters: - filepath_or_buffer (str, path object, or file-like object) – String, path object (implementing
os.PathLike[str]
), or file-like object implementing a textread()
function.The string could be a URL. Valid URL schemes include http, ftp, s3, and file. For file URLs, a host is expected. A local file could be:file://localhost/path/to/table.csv
. - colspecs (list of tuple (int, int) or 'infer'. optional) – A list of tuples giving the extents of the fixed-width fields of each line as half-open intervals (i.e., [from, to[ ). String value ‘infer’ can be used to instruct the parser to try detecting the column specifications from the first 100 rows of the data which are not being skipped via skiprows (default=’infer’).
- widths (list of int, optional) – A list of field widths which can be used instead of ‘colspecs’ if the intervals are contiguous.
- infer_nrows (int, default 100) – The number of rows to consider when letting the parser determine the colspecs.
- **kwds (optional) – Optional keyword arguments can be passed to
TextFileReader
.
Returns: A comma-separated values (csv) file is returned as two-dimensional data structure with labeled axes.
Return type: DeferredDataFrame or TextFileReader
Differences from pandas
This operation has no known divergences from the pandas API.
See also
DeferredDataFrame.to_csv()
- Write DeferredDataFrame to a comma-separated values (csv) file.
read_csv()
- Read a comma-separated values (csv) file into DeferredDataFrame.
Examples
NOTE: These examples are pulled directly from the pandas documentation for convenience. Usage of the Beam DataFrame API will look different because it is a deferred API.
>>> pd.read_fwf('data.csv')
- filepath_or_buffer (str, path object, or file-like object) – String, path object (implementing
-
apache_beam.dataframe.io.
read_json
(path, *args, **kwargs)[source]¶ Convert a JSON string to pandas object.
Parameters: - path_or_buf (a valid JSON str, path object or file-like object) –
Any valid string path is acceptable. The string could be a URL. Valid URL schemes include http, ftp, s3, and file. For file URLs, a host is expected. A local file could be:
file://localhost/path/to/table.json
.If you want to pass in a path object, pandas accepts any
os.PathLike
.By file-like object, we refer to objects with a
read()
method, such as a file handle (e.g. via builtinopen
function) orStringIO
. - orient (str) –
Indication of expected JSON string format. Compatible JSON strings can be produced by
to_json()
with a corresponding orient value. The set of possible orients is:'split'
: dict like{index -> [index], columns -> [columns], data -> [values]}
'records'
: list like[{column -> value}, ... , {column -> value}]
'index'
: dict like{index -> {column -> value}}
'columns'
: dict like{column -> {index -> value}}
'values'
: just the values array
The allowed and default values depend on the value of the typ parameter.
- when
typ == 'series'
,- allowed orients are
{'split','records','index'}
- default is
'index'
- The DeferredSeries index must be unique for orient
'index'
.
- allowed orients are
- when
typ == 'frame'
,- allowed orients are
{'split','records','index', 'columns','values', 'table'}
- default is
'columns'
- The DeferredDataFrame index must be unique for orients
'index'
and'columns'
. - The DeferredDataFrame columns must be unique for orients
'index'
,'columns'
, and'records'
.
- allowed orients are
- typ ({'frame', 'series'}, default 'frame') – The type of object to recover.
- dtype (bool or dict, default None) –
If True, infer dtypes; if a dict of column to dtype, then use those; if False, then don’t infer dtypes at all, applies only to the data.
For all
orient
values except'table'
, default is True.Changed in version 0.25.0: Not applicable for
orient='table'
. - convert_axes (bool, default None) –
Try to convert the axes to the proper dtypes.
For all
orient
values except'table'
, default is True.Changed in version 0.25.0: Not applicable for
orient='table'
. - convert_dates (bool or list of str, default True) – If True then default datelike columns may be converted (depending on keep_default_dates). If False, no dates will be converted. If a list of column names, then those columns will be converted and default datelike columns may also be converted (depending on keep_default_dates).
- keep_default_dates (bool, default True) –
If parsing dates (convert_dates is not False), then try to parse the default datelike columns. A column label is datelike if
- it ends with
'_at'
, - it ends with
'_time'
, - it begins with
'timestamp'
, - it is
'modified'
, or - it is
'date'
.
- it ends with
- numpy (bool, default False) –
Direct decoding to numpy arrays. Supports numeric data only, but non-numeric column and index labels are supported. Note also that the JSON ordering MUST be the same for each term if numpy=True.
Deprecated since version 1.0.0.
- precise_float (bool, default False) – Set to enable usage of higher precision (strtod) function when decoding string to double values. Default (False) is to use fast but less precise builtin functionality.
- date_unit (str, default None) – The timestamp unit to detect if converting dates. The default behaviour is to try and detect the correct precision, but if this is not desired then pass one of ‘s’, ‘ms’, ‘us’ or ‘ns’ to force parsing only seconds, milliseconds, microseconds or nanoseconds respectively.
- encoding (str, default is 'utf-8') – The encoding to use to decode py3 bytes.
- encoding_errors (str, optional, default "strict") –
How encoding errors are treated. List of possible values .
New in version 1.3.0.
- lines (bool, default False) – Read the file as a json object per line.
- chunksize (int, optional) –
Return JsonReader object for iteration. See the line-delimited json docs for more information on
chunksize
. This can only be passed if lines=True. If this is None, the file will be read into memory all at once.Changed in version 1.2:
JsonReader
is a context manager. - compression (str or dict, default 'infer') –
For on-the-fly decompression of on-disk data. If ‘infer’ and ‘path_or_buf’ is path-like, then detect compression from the following extensions: ‘.gz’, ‘.bz2’, ‘.zip’, ‘.xz’, ‘.zst’, ‘.tar’, ‘.tar.gz’, ‘.tar.xz’ or ‘.tar.bz2’ (otherwise no compression). If using ‘zip’ or ‘tar’, the ZIP file must contain only one data file to be read in. Set to
None
for no decompression. Can also be a dict with key'method'
set to one of {'zip'
,'gzip'
,'bz2'
,'zstd'
,'tar'
} and other key-value pairs are forwarded tozipfile.ZipFile
,gzip.GzipFile
,bz2.BZ2File
,zstandard.ZstdDecompressor
ortarfile.TarFile
, respectively. As an example, the following could be passed for Zstandard decompression using a custom compression dictionary:compression={'method': 'zstd', 'dict_data': my_compression_dict}
.New in version 1.5.0: Added support for .tar files.
Changed in version 1.4.0: Zstandard support.
- nrows (int, optional) –
The number of lines from the line-delimited jsonfile that has to be read. This can only be passed if lines=True. If this is None, all the rows will be returned.
New in version 1.1.
- storage_options (dict, optional) –
Extra options that make sense for a particular storage connection, e.g. host, port, username, password, etc. For HTTP(S) URLs the key-value pairs are forwarded to
urllib.request.Request
as header options. For other URLs (e.g. starting with “s3://”, and “gcs://”) the key-value pairs are forwarded tofsspec.open
. Please seefsspec
andurllib
for more details, and for more examples on storage options refer here.New in version 1.2.0.
Returns: The type returned depends on the value of typ.
Return type: Differences from pandas
This operation has no known divergences from the pandas API.
See also
DeferredDataFrame.to_json()
- Convert a DeferredDataFrame to a JSON string.
DeferredSeries.to_json()
- Convert a DeferredSeries to a JSON string.
json_normalize()
- Normalize semi-structured JSON data into a flat table.
Notes
Specific to
orient='table'
, if aDeferredDataFrame
with a literalIndex
name of index gets written withto_json()
, the subsequent read operation will incorrectly set theIndex
name toNone
. This is because index is also used byDeferredDataFrame.to_json()
to denote a missingIndex
name, and the subsequentread_json()
operation cannot distinguish between the two. The same limitation is encountered with aMultiIndex
and any names beginning with'level_'
.Examples
NOTE: These examples are pulled directly from the pandas documentation for convenience. Usage of the Beam DataFrame API will look different because it is a deferred API.
>>> df = pd.DataFrame([['a', 'b'], ['c', 'd']], ... index=['row 1', 'row 2'], ... columns=['col 1', 'col 2']) Encoding/decoding a Dataframe using ``'split'`` formatted JSON: >>> df.to_json(orient='split') '{"columns":["col 1","col 2"],"index":["row 1","row 2"],"data":[["a","b"],["c","d"]]}' >>> pd.read_json(_, orient='split') col 1 col 2 row 1 a b row 2 c d Encoding/decoding a Dataframe using ``'index'`` formatted JSON: >>> df.to_json(orient='index') '{"row 1":{"col 1":"a","col 2":"b"},"row 2":{"col 1":"c","col 2":"d"}}' >>> pd.read_json(_, orient='index') col 1 col 2 row 1 a b row 2 c d Encoding/decoding a Dataframe using ``'records'`` formatted JSON. Note that index labels are not preserved with this encoding. >>> df.to_json(orient='records') '[{"col 1":"a","col 2":"b"},{"col 1":"c","col 2":"d"}]' >>> pd.read_json(_, orient='records') col 1 col 2 0 a b 1 c d Encoding with Table Schema >>> df.to_json(orient='table') '{"schema":{"fields":[{"name":"index","type":"string"},{"name":"col 1","type":"string"},{"name":"col 2","type":"string"}],"primaryKey":["index"],"pandas_version":"1.4.0"},"data":[{"index":"row 1","col 1":"a","col 2":"b"},{"index":"row 2","col 1":"c","col 2":"d"}]}'
- path_or_buf (a valid JSON str, path object or file-like object) –
-
apache_beam.dataframe.io.
to_json
(df, path, orient=None, *args, **kwargs)[source]¶ Convert the object to a JSON string.
Note NaN’s and None will be converted to null and datetime objects will be converted to UNIX timestamps.
Parameters: - path_or_buf (str, path object, file-like object, or None, default None) – String, path object (implementing os.PathLike[str]), or file-like object implementing a write() function. If None, the result is returned as a string.
- orient (str) –
Indication of expected JSON string format.
- DeferredSeries:
- default is ‘index’
- allowed values are: {‘split’, ‘records’, ‘index’, ‘table’}.
- DeferredDataFrame:
- default is ‘columns’
- allowed values are: {‘split’, ‘records’, ‘index’, ‘columns’, ‘values’, ‘table’}.
- The format of the JSON string:
- ’split’ : dict like {‘index’ -> [index], ‘columns’ -> [columns], ‘data’ -> [values]}
- ’records’ : list like [{column -> value}, … , {column -> value}]
- ’index’ : dict like {index -> {column -> value}}
- ’columns’ : dict like {column -> {index -> value}}
- ’values’ : just the values array
- ’table’ : dict like {‘schema’: {schema}, ‘data’: {data}}
Describing the data, where data component is like
orient='records'
.
- DeferredSeries:
- date_format ({None, 'epoch', 'iso'}) – Type of date conversion. ‘epoch’ = epoch milliseconds,
‘iso’ = ISO8601. The default depends on the orient. For
orient='table'
, the default is ‘iso’. For all other orients, the default is ‘epoch’. - double_precision (int, default 10) – The number of decimal places to use when encoding floating point values.
- force_ascii (bool, default True) – Force encoded string to be ASCII.
- date_unit (str, default 'ms' (milliseconds)) – The time unit to encode to, governs timestamp and ISO8601 precision. One of ‘s’, ‘ms’, ‘us’, ‘ns’ for second, millisecond, microsecond, and nanosecond respectively.
- default_handler (callable, default None) – Handler to call if object cannot otherwise be converted to a suitable format for JSON. Should receive a single argument which is the object to convert and return a serialisable object.
- lines (bool, default False) – If ‘orient’ is ‘records’ write out line-delimited json format. Will throw ValueError if incorrect ‘orient’ since others are not list-like.
- compression (str or dict, default 'infer') –
For on-the-fly compression of the output data. If ‘infer’ and ‘path_or_buf’ is path-like, then detect compression from the following extensions: ‘.gz’, ‘.bz2’, ‘.zip’, ‘.xz’, ‘.zst’, ‘.tar’, ‘.tar.gz’, ‘.tar.xz’ or ‘.tar.bz2’ (otherwise no compression). Set to
None
for no compression. Can also be a dict with key'method'
set to one of {'zip'
,'gzip'
,'bz2'
,'zstd'
,'tar'
} and other key-value pairs are forwarded tozipfile.ZipFile
,gzip.GzipFile
,bz2.BZ2File
,zstandard.ZstdCompressor
ortarfile.TarFile
, respectively. As an example, the following could be passed for faster compression and to create a reproducible gzip archive:compression={'method': 'gzip', 'compresslevel': 1, 'mtime': 1}
.New in version 1.5.0: Added support for .tar files.
Changed in version 1.4.0: Zstandard support.
- index (bool, default True) – Whether to include the index values in the JSON string. Not
including the index (
index=False
) is only supported when orient is ‘split’ or ‘table’. - indent (int, optional) –
Length of whitespace used to indent each record.
New in version 1.0.0.
- storage_options (dict, optional) –
Extra options that make sense for a particular storage connection, e.g. host, port, username, password, etc. For HTTP(S) URLs the key-value pairs are forwarded to
urllib.request.Request
as header options. For other URLs (e.g. starting with “s3://”, and “gcs://”) the key-value pairs are forwarded tofsspec.open
. Please seefsspec
andurllib
for more details, and for more examples on storage options refer here.New in version 1.2.0.
Returns: If path_or_buf is None, returns the resulting json format as a string. Otherwise returns None.
Return type: Differences from pandas
This operation has no known divergences from the pandas API.
See also
read_json()
- Convert a JSON string to pandas object.
Notes
The behavior of
indent=0
varies from the stdlib, which does not indent the output but does insert newlines. Currently,indent=0
and the defaultindent=None
are equivalent in pandas, though this may change in a future release.orient='table'
contains a ‘pandas_version’ field under ‘schema’. This stores the version of pandas used in the latest revision of the schema.Examples
NOTE: These examples are pulled directly from the pandas documentation for convenience. Usage of the Beam DataFrame API will look different because it is a deferred API.
>>> import json >>> df = pd.DataFrame( ... [["a", "b"], ["c", "d"]], ... index=["row 1", "row 2"], ... columns=["col 1", "col 2"], ... ) >>> result = df.to_json(orient="split") >>> parsed = json.loads(result) >>> json.dumps(parsed, indent=4) { "columns": [ "col 1", "col 2" ], "index": [ "row 1", "row 2" ], "data": [ [ "a", "b" ], [ "c", "d" ] ] } Encoding/decoding a Dataframe using ``'records'`` formatted JSON. Note that index labels are not preserved with this encoding. >>> result = df.to_json(orient="records") >>> parsed = json.loads(result) >>> json.dumps(parsed, indent=4) [ { "col 1": "a", "col 2": "b" }, { "col 1": "c", "col 2": "d" } ] Encoding/decoding a Dataframe using ``'index'`` formatted JSON: >>> result = df.to_json(orient="index") >>> parsed = json.loads(result) >>> json.dumps(parsed, indent=4) { "row 1": { "col 1": "a", "col 2": "b" }, "row 2": { "col 1": "c", "col 2": "d" } } Encoding/decoding a Dataframe using ``'columns'`` formatted JSON: >>> result = df.to_json(orient="columns") >>> parsed = json.loads(result) >>> json.dumps(parsed, indent=4) { "col 1": { "row 1": "a", "row 2": "c" }, "col 2": { "row 1": "b", "row 2": "d" } } Encoding/decoding a Dataframe using ``'values'`` formatted JSON: >>> result = df.to_json(orient="values") >>> parsed = json.loads(result) >>> json.dumps(parsed, indent=4) [ [ "a", "b" ], [ "c", "d" ] ] Encoding with Table Schema: >>> result = df.to_json(orient="table") >>> parsed = json.loads(result) >>> json.dumps(parsed, indent=4) { "schema": { "fields": [ { "name": "index", "type": "string" }, { "name": "col 1", "type": "string" }, { "name": "col 2", "type": "string" } ], "primaryKey": [ "index" ], "pandas_version": "1.4.0" }, "data": [ { "index": "row 1", "col 1": "a", "col 2": "b" }, { "index": "row 2", "col 1": "c", "col 2": "d" } ] }
-
apache_beam.dataframe.io.
read_html
(path, *args, **kwargs)[source]¶ Read HTML tables into a
list
ofDataFrame
objects.Parameters: - io (str, path object, or file-like object) – String, path object (implementing
os.PathLike[str]
), or file-like object implementing a stringread()
function. The string can represent a URL or the HTML itself. Note that lxml only accepts the http, ftp and file url protocols. If you have a URL that starts with'https'
you might try removing the's'
. - match (str or compiled regular expression, optional) – The set of tables containing text matching this regex or string will be returned. Unless the HTML is extremely simple you will probably need to pass a non-empty string here. Defaults to ‘.+’ (match any non-empty string). The default value will return all tables contained on a page. This value is converted to a regular expression so that there is consistent behavior between Beautiful Soup and lxml.
- flavor (str, optional) – The parsing engine to use. ‘bs4’ and ‘html5lib’ are synonymous with
each other, they are both there for backwards compatibility. The
default of
None
tries to uselxml
to parse and if that fails it falls back onbs4
+html5lib
. - header (int or list-like, optional) – The row (or list of rows for a
MultiIndex
) to use to make the columns headers. - index_col (int or list-like, optional) – The column (or list of columns) to use to create the index.
- skiprows (int, list-like or slice, optional) – Number of rows to skip after parsing the column integer. 0-based. If a sequence of integers or a slice is given, will skip the rows indexed by that sequence. Note that a single element sequence means ‘skip the nth row’ whereas an integer means ‘skip n rows’.
- attrs (dict, optional) –
This is a dictionary of attributes that you can pass to use to identify the table in the HTML. These are not checked for validity before being passed to lxml or Beautiful Soup. However, these attributes must be valid HTML table attributes to work correctly. For example,
attrs = {'id': 'table'}
is a valid attribute dictionary because the ‘id’ HTML tag attribute is a valid HTML attribute for any HTML tag as per this document.
attrs = {'asdf': 'table'}
is not a valid attribute dictionary because ‘asdf’ is not a valid HTML attribute even if it is a valid XML attribute. Valid HTML 4.01 table attributes can be found here. A working draft of the HTML 5 spec can be found here. It contains the latest information on table attributes for the modern web.
- parse_dates (bool, optional) – See
read_csv()
for more details. - thousands (str, optional) – Separator to use to parse thousands. Defaults to
','
. - encoding (str, optional) – The encoding used to decode the web page. Defaults to
None
.``None`` preserves the previous encoding behavior, which depends on the underlying parser library (e.g., the parser library will try to use the encoding provided by the document). - decimal (str, default '.') – Character to recognize as decimal point (e.g. use ‘,’ for European data).
- converters (dict, default None) – Dict of functions for converting values in certain columns. Keys can either be integers or column labels, values are functions that take one input argument, the cell (not column) content, and return the transformed content.
- na_values (iterable, default None) – Custom NA values.
- keep_default_na (bool, default True) – If na_values are specified and keep_default_na is False the default NaN values are overridden, otherwise they’re appended to.
- displayed_only (bool, default True) – Whether elements with “display: none” should be parsed.
- extract_links ({None, "all", "header", "body", "footer"}) –
Table elements in the specified section(s) with <a> tags will have their href extracted.
New in version 1.5.0.
Returns: A list of DeferredDataFrames.
Return type: dfs
Differences from pandas
This operation has no known divergences from the pandas API.
See also
read_csv()
- Read a comma-separated values (csv) file into DeferredDataFrame.
Notes
Before using this function you should read the gotchas about the HTML parsing libraries.
Expect to do some cleanup after you call this function. For example, you might need to manually assign column names if the column names are converted to NaN when you pass the header=0 argument. We try to assume as little as possible about the structure of the table and push the idiosyncrasies of the HTML contained in the table to the user.
This function searches for
<table>
elements and only for<tr>
and<th>
rows and<td>
elements within each<tr>
or<th>
element in the table.<td>
stands for “table data”. This function attempts to properly handlecolspan
androwspan
attributes. If the function has a<thead>
argument, it is used to construct the header, otherwise the function attempts to find the header within the body (by putting rows with only<th>
elements into the header).Similar to
read_csv()
the header argument is applied after skiprows is applied.This function will always return a list of
DeferredDataFrame
or it will fail, e.g., it will not return an empty list.Examples
NOTE: These examples are pulled directly from the pandas documentation for convenience. Usage of the Beam DataFrame API will look different because it is a deferred API.
See the :ref:`read_html documentation in the IO section of the docs <io.read_html>` for some examples of reading in HTML tables.
- io (str, path object, or file-like object) – String, path object (implementing
-
apache_beam.dataframe.io.
to_html
(df, path, *args, **kwargs)[source]¶ Render a DataFrame as an HTML table.
Parameters: - buf (str, Path or StringIO-like, optional, default None) – Buffer to write to. If None, the output is returned as a string.
- columns (sequence, optional, default None) – The subset of columns to write. Writes all columns by default.
- col_space (str or int, list or dict of int or str, optional) –
The minimum width of each column in CSS length units. An int is assumed to be px units.
New in version 0.25.0: Ability to use str.
- header (bool, optional) – Whether to print column labels, default True.
- index (bool, optional, default True) – Whether to print index (row) labels.
- na_rep (str, optional, default 'NaN') – String representation of
NaN
to use. - formatters (list, tuple or dict of one-param. functions, optional) – Formatter functions to apply to columns’ elements by position or name. The result of each function must be a unicode string. List/tuple must be of length equal to the number of columns.
- float_format (one-parameter function, optional, default None) –
Formatter function to apply to columns’ elements if they are floats. This function must return a unicode string and will be applied only to the non-
NaN
elements, withNaN
being handled byna_rep
.Changed in version 1.2.0.
- sparsify (bool, optional, default True) – Set to False for a DeferredDataFrame with a hierarchical index to print every multiindex key at each row.
- index_names (bool, optional, default True) – Prints the names of the indexes.
- justify (str, default None) –
How to justify the column labels. If None uses the option from the print configuration (controlled by set_option), ‘right’ out of the box. Valid values are
- left
- right
- center
- justify
- justify-all
- start
- end
- inherit
- match-parent
- initial
- unset.
- max_rows (int, optional) – Maximum number of rows to display in the console.
- max_cols (int, optional) – Maximum number of columns to display in the console.
- show_dimensions (bool, default False) – Display DeferredDataFrame dimensions (number of rows by number of columns).
- decimal (str, default '.') – Character recognized as decimal separator, e.g. ‘,’ in Europe.
- bold_rows (bool, default True) – Make the row labels bold in the output.
- classes (str or list or tuple, default None) – CSS class(es) to apply to the resulting html table.
- escape (bool, default True) – Convert the characters <, >, and & to HTML-safe sequences.
- notebook ({True, False}, default False) – Whether the generated HTML is for IPython Notebook.
- border (int) – A
border=border
attribute is included in the opening <table> tag. Defaultpd.options.display.html.border
. - table_id (str, optional) – A css id is included in the opening <table> tag if specified.
- render_links (bool, default False) – Convert URLs to HTML links.
- encoding (str, default "utf-8") –
Set character encoding.
New in version 1.0.
Returns: If buf is None, returns the result as a string. Otherwise returns None.
Return type: Differences from pandas
This operation has no known divergences from the pandas API.
See also
to_string()
- Convert DeferredDataFrame to a string.
-
class
apache_beam.dataframe.io.
ReadViaPandas
(format, *args, include_indexes=False, objects_as_strings=True, **kwargs)[source]¶
-
apache_beam.dataframe.io.
read_excel
(path, *args, **kwargs)¶ Read an Excel file into a pandas DataFrame.
Supports xls, xlsx, xlsm, xlsb, odf, ods and odt file extensions read from a local filesystem or URL. Supports an option to read a single sheet or a list of sheets.
Parameters: - io (str, bytes, ExcelFile, xlrd.Book, path object, or file-like object) –
Any valid string path is acceptable. The string could be a URL. Valid URL schemes include http, ftp, s3, and file. For file URLs, a host is expected. A local file could be:
file://localhost/path/to/table.xlsx
.If you want to pass in a path object, pandas accepts any
os.PathLike
.By file-like object, we refer to objects with a
read()
method, such as a file handle (e.g. via builtinopen
function) orStringIO
. - sheet_name (str, int, list, or None, default 0) –
Strings are used for sheet names. Integers are used in zero-indexed sheet positions (chart sheets do not count as a sheet position). Lists of strings/integers are used to request multiple sheets. Specify None to get all worksheets.
Available cases:
- Defaults to
0
: 1st sheet as a DeferredDataFrame 1
: 2nd sheet as a DeferredDataFrame"Sheet1"
: Load sheet with name “Sheet1”[0, 1, "Sheet5"]
: Load first, second and sheet named “Sheet5” as a dict of DeferredDataFrame- None: All worksheets.
- Defaults to
- header (int, list of int, default 0) – Row (0-indexed) to use for the column labels of the parsed
DeferredDataFrame. If a list of integers is passed those row positions will
be combined into a
MultiIndex
. Use None if there is no header. - names (array-like, default None) – List of column names to use. If file contains no header row, then you should explicitly pass header=None.
- index_col (int, list of int, default None) –
Column (0-indexed) to use as the row labels of the DeferredDataFrame. Pass None if there is no such column. If a list is passed, those columns will be combined into a
MultiIndex
. If a subset of data is selected withusecols
, index_col is based on the subset.Missing values will be forward filled to allow roundtripping with
to_excel
formerged_cells=True
. To avoid forward filling the missing values useset_index
after reading the data instead ofindex_col
. - usecols (str, list-like, or callable, default None) –
- If None, then parse all columns.
- If str, then indicates comma separated list of Excel column letters and column ranges (e.g. “A:E” or “A,C,E:F”). Ranges are inclusive of both sides.
- If list of int, then indicates list of column numbers to be parsed (0-indexed).
- If list of string, then indicates list of column names to be parsed.
- If callable, then evaluate each column name against it and parse the
column if the callable returns
True
.
Returns a subset of the columns according to behavior above.
- squeeze (bool, default False) –
If the parsed data only contains one column then return a DeferredSeries.
Deprecated since version 1.4.0: Append
.squeeze("columns")
to the call toread_excel
to squeeze the data. - dtype (Type name or dict of column -> type, default None) – Data type for data or columns. E.g. {‘a’: np.float64, ‘b’: np.int32} Use object to preserve data as stored in Excel and not interpret dtype. If converters are specified, they will be applied INSTEAD of dtype conversion.
- engine (str, default None) –
If io is not a buffer or path, this must be set to identify io. Supported engines: “xlrd”, “openpyxl”, “odf”, “pyxlsb”. Engine compatibility :
- ”xlrd” supports old-style Excel files (.xls).
- ”openpyxl” supports newer Excel file formats.
- ”odf” supports OpenDocument file formats (.odf, .ods, .odt).
- ”pyxlsb” supports Binary Excel files.
Changed in version 1.2.0: The engine xlrd now only supports old-style
.xls
files. Whenengine=None
, the following logic will be used to determine the engine:- If
path_or_buffer
is an OpenDocument format (.odf, .ods, .odt), then odf will be used. - Otherwise if
path_or_buffer
is an xls format,xlrd
will be used. - Otherwise if
path_or_buffer
is in xlsb format,pyxlsb
will be used.New in version 1.3.0.
- Otherwise
openpyxl
will be used.Changed in version 1.3.0.
- converters (dict, default None) – Dict of functions for converting values in certain columns. Keys can either be integers or column labels, values are functions that take one input argument, the Excel cell content, and return the transformed content.
- true_values (list, default None) – Values to consider as True.
- false_values (list, default None) – Values to consider as False.
- skiprows (list-like, int, or callable, optional) – Line numbers to skip (0-indexed) or number of lines to skip (int) at the
start of the file. If callable, the callable function will be evaluated
against the row indices, returning True if the row should be skipped and
False otherwise. An example of a valid callable argument would be
lambda x: x in [0, 2]
. - nrows (int, default None) – Number of rows to parse.
- na_values (scalar, str, list-like, or dict, default None) – Additional strings to recognize as NA/NaN. If dict passed, specific per-column NA values. By default the following values are interpreted as NaN: ‘’, ‘#N/A’, ‘#N/A N/A’, ‘#NA’, ‘-1.#IND’, ‘-1.#QNAN’, ‘-NaN’, ‘-nan’, ‘1.#IND’, ‘1.#QNAN’, ‘<NA>’, ‘N/A’, ‘NA’, ‘NULL’, ‘NaN’, ‘n/a’, ‘nan’, ‘null’.
- keep_default_na (bool, default True) –
Whether or not to include the default NaN values when parsing the data. Depending on whether na_values is passed in, the behavior is as follows:
- If keep_default_na is True, and na_values are specified, na_values is appended to the default NaN values used for parsing.
- If keep_default_na is True, and na_values are not specified, only the default NaN values are used for parsing.
- If keep_default_na is False, and na_values are specified, only the NaN values specified na_values are used for parsing.
- If keep_default_na is False, and na_values are not specified, no strings will be parsed as NaN.
Note that if na_filter is passed in as False, the keep_default_na and na_values parameters will be ignored.
- na_filter (bool, default True) – Detect missing value markers (empty strings and the value of na_values). In data without any NAs, passing na_filter=False can improve the performance of reading a large file.
- verbose (bool, default False) – Indicate number of NA values placed in non-numeric columns.
- parse_dates (bool, list-like, or dict, default False) –
The behavior is as follows:
- bool. If True -> try parsing the index.
- list of int or names. e.g. If [1, 2, 3] -> try parsing columns 1, 2, 3 each as a separate date column.
- list of lists. e.g. If [[1, 3]] -> combine columns 1 and 3 and parse as a single date column.
- dict, e.g. {‘foo’ : [1, 3]} -> parse columns 1, 3 as date and call result ‘foo’
If a column or index contains an unparsable date, the entire column or index will be returned unaltered as an object data type. If you don`t want to parse some cells as date just change their type in Excel to “Text”. For non-standard datetime parsing, use
pd.to_datetime
afterpd.read_excel
.Note: A fast-path exists for iso8601-formatted dates.
- date_parser (function, optional) – Function to use for converting a sequence of string columns to an array of
datetime instances. The default uses
dateutil.parser.parser
to do the conversion. Pandas will try to call date_parser in three different ways, advancing to the next if an exception occurs: 1) Pass one or more arrays (as defined by parse_dates) as arguments; 2) concatenate (row-wise) the string values from the columns defined by parse_dates into a single array and pass that; and 3) call date_parser once for each row using one or more strings (corresponding to the columns defined by parse_dates) as arguments. - thousands (str, default None) – Thousands separator for parsing string columns to numeric. Note that this parameter is only necessary for columns stored as TEXT in Excel, any numeric columns will automatically be parsed, regardless of display format.
- decimal (str, default '.') –
Character to recognize as decimal point for parsing string columns to numeric. Note that this parameter is only necessary for columns stored as TEXT in Excel, any numeric columns will automatically be parsed, regardless of display format.(e.g. use ‘,’ for European data).
New in version 1.4.0.
- comment (str, default None) – Comments out remainder of line. Pass a character or characters to this argument to indicate comments in the input file. Any data between the comment string and the end of the current line is ignored.
- skipfooter (int, default 0) – Rows at the end to skip (0-indexed).
- convert_float (bool, default True) –
Convert integral floats to int (i.e., 1.0 –> 1). If False, all numeric data will be read in as floats: Excel stores all numbers as floats internally.
Deprecated since version 1.3.0: convert_float will be removed in a future version
- mangle_dupe_cols (bool, default True) –
Duplicate columns will be specified as ‘X’, ‘X.1’, …’X.N’, rather than ‘X’…’X’. Passing in False will cause data to be overwritten if there are duplicate names in the columns.
Deprecated since version 1.5.0: Not implemented, and a new argument to specify the pattern for the names of duplicated columns will be added instead
- storage_options (dict, optional) –
Extra options that make sense for a particular storage connection, e.g. host, port, username, password, etc. For HTTP(S) URLs the key-value pairs are forwarded to
urllib.request.Request
as header options. For other URLs (e.g. starting with “s3://”, and “gcs://”) the key-value pairs are forwarded tofsspec.open
. Please seefsspec
andurllib
for more details, and for more examples on storage options refer here.New in version 1.2.0.
Returns: DeferredDataFrame from the passed in Excel file. See notes in sheet_name argument for more information on when a dict of DeferredDataFrames is returned.
Return type: DeferredDataFrame or dict of DeferredDataFrames
Differences from pandas
This operation has no known divergences from the pandas API.
See also
DeferredDataFrame.to_excel()
- Write DeferredDataFrame to an Excel file.
DeferredDataFrame.to_csv()
- Write DeferredDataFrame to a comma-separated values (csv) file.
read_csv()
- Read a comma-separated values (csv) file into DeferredDataFrame.
read_fwf()
- Read a table of fixed-width formatted lines into DeferredDataFrame.
Examples
NOTE: These examples are pulled directly from the pandas documentation for convenience. Usage of the Beam DataFrame API will look different because it is a deferred API.
The file can be read using the file name as string or an open file object: >>> pd.read_excel('tmp.xlsx', index_col=0) Name Value 0 string1 1 1 string2 2 2 #Comment 3 >>> pd.read_excel(open('tmp.xlsx', 'rb'), ... sheet_name='Sheet3') Unnamed: 0 Name Value 0 0 string1 1 1 1 string2 2 2 2 #Comment 3 Index and header can be specified via the `index_col` and `header` arguments >>> pd.read_excel('tmp.xlsx', index_col=None, header=None) 0 1 2 0 NaN Name Value 1 0.0 string1 1 2 1.0 string2 2 3 2.0 #Comment 3 Column types are inferred but can be explicitly specified >>> pd.read_excel('tmp.xlsx', index_col=0, ... dtype={'Name': str, 'Value': float}) Name Value 0 string1 1.0 1 string2 2.0 2 #Comment 3.0 True, False, and NA values, and thousands separators have defaults, but can be explicitly specified, too. Supply the values you would like as strings or lists of strings! >>> pd.read_excel('tmp.xlsx', index_col=0, ... na_values=['string1', 'string2']) Name Value 0 NaN 1 1 NaN 2 2 #Comment 3 Comment lines in the excel input file can be skipped using the `comment` kwarg >>> pd.read_excel('tmp.xlsx', index_col=0, comment='#') Name Value 0 string1 1.0 1 string2 2.0 2 None NaN
- io (str, bytes, ExcelFile, xlrd.Book, path object, or file-like object) –
-
apache_beam.dataframe.io.
read_feather
(path, *args, **kwargs)¶ Load a feather-format object from the file path.
Parameters: - path (str, path object, or file-like object) – String, path object (implementing
os.PathLike[str]
), or file-like object implementing a binaryread()
function. The string could be a URL. Valid URL schemes include http, ftp, s3, and file. For file URLs, a host is expected. A local file could be:file://localhost/path/to/table.feather
. - columns (sequence, default None) – If not provided, all columns are read.
- use_threads (bool, default True) – Whether to parallelize reading using multiple threads.
- storage_options (dict, optional) –
Extra options that make sense for a particular storage connection, e.g. host, port, username, password, etc. For HTTP(S) URLs the key-value pairs are forwarded to
urllib.request.Request
as header options. For other URLs (e.g. starting with “s3://”, and “gcs://”) the key-value pairs are forwarded tofsspec.open
. Please seefsspec
andurllib
for more details, and for more examples on storage options refer here.New in version 1.2.0.
Returns: Return type: type of object stored in file
Differences from pandas
This operation has no known divergences from the pandas API.
- path (str, path object, or file-like object) – String, path object (implementing
-
apache_beam.dataframe.io.
read_parquet
(path, *args, **kwargs)¶ Load a parquet object from the file path, returning a DataFrame.
Parameters: - path (str, path object or file-like object) – String, path object (implementing
os.PathLike[str]
), or file-like object implementing a binaryread()
function. The string could be a URL. Valid URL schemes include http, ftp, s3, gs, and file. For file URLs, a host is expected. A local file could be:file://localhost/path/to/table.parquet
. A file URL can also be a path to a directory that contains multiple partitioned parquet files. Both pyarrow and fastparquet support paths to directories as well as file URLs. A directory path could be:file://localhost/path/to/tables
ors3://bucket/partition_dir
. - engine ({'auto', 'pyarrow', 'fastparquet'}, default 'auto') – Parquet library to use. If ‘auto’, then the option
io.parquet.engine
is used. The defaultio.parquet.engine
behavior is to try ‘pyarrow’, falling back to ‘fastparquet’ if ‘pyarrow’ is unavailable. - columns (list, default=None) – If not None, only these columns will be read from the file.
- storage_options (dict, optional) –
Extra options that make sense for a particular storage connection, e.g. host, port, username, password, etc. For HTTP(S) URLs the key-value pairs are forwarded to
urllib.request.Request
as header options. For other URLs (e.g. starting with “s3://”, and “gcs://”) the key-value pairs are forwarded tofsspec.open
. Please seefsspec
andurllib
for more details, and for more examples on storage options refer here.New in version 1.3.0.
- use_nullable_dtypes (bool, default False) –
If True, use dtypes that use
pd.NA
as missing value indicator for the resulting DeferredDataFrame. (only applicable for thepyarrow
engine) As new dtypes are added that supportpd.NA
in the future, the output with this option will change to use those dtypes. Note: this is an experimental option, and behaviour (e.g. additional support dtypes) may change without notice.New in version 1.2.0.
- **kwargs – Any additional kwargs are passed to the engine.
Returns: Return type: Differences from pandas
This operation has no known divergences from the pandas API.
- path (str, path object or file-like object) – String, path object (implementing
-
apache_beam.dataframe.io.
read_sas
(path, *args, **kwargs)¶ Read SAS files stored as either XPORT or SAS7BDAT format files.
Parameters: - filepath_or_buffer (str, path object, or file-like object) – String, path object (implementing
os.PathLike[str]
), or file-like object implementing a binaryread()
function. The string could be a URL. Valid URL schemes include http, ftp, s3, and file. For file URLs, a host is expected. A local file could be:file://localhost/path/to/table.sas
. - format (str {'xport', 'sas7bdat'} or None) – If None, file format is inferred from file extension. If ‘xport’ or ‘sas7bdat’, uses the corresponding format.
- index (identifier of index column, defaults to None) – Identifier of column that should be used as index of the DeferredDataFrame.
- encoding (str, default is None) – Encoding for text data. If None, text data are stored as raw bytes.
- chunksize (int) –
Read file chunksize lines at a time, returns iterator.
Changed in version 1.2:
TextFileReader
is a context manager. - iterator (bool, defaults to False) –
If True, returns an iterator for reading the file incrementally.
Changed in version 1.2:
TextFileReader
is a context manager. - compression (str or dict, default 'infer') –
For on-the-fly decompression of on-disk data. If ‘infer’ and ‘filepath_or_buffer’ is path-like, then detect compression from the following extensions: ‘.gz’, ‘.bz2’, ‘.zip’, ‘.xz’, ‘.zst’, ‘.tar’, ‘.tar.gz’, ‘.tar.xz’ or ‘.tar.bz2’ (otherwise no compression). If using ‘zip’ or ‘tar’, the ZIP file must contain only one data file to be read in. Set to
None
for no decompression. Can also be a dict with key'method'
set to one of {'zip'
,'gzip'
,'bz2'
,'zstd'
,'tar'
} and other key-value pairs are forwarded tozipfile.ZipFile
,gzip.GzipFile
,bz2.BZ2File
,zstandard.ZstdDecompressor
ortarfile.TarFile
, respectively. As an example, the following could be passed for Zstandard decompression using a custom compression dictionary:compression={'method': 'zstd', 'dict_data': my_compression_dict}
.New in version 1.5.0: Added support for .tar files.
Returns: - DeferredDataFrame if iterator=False and chunksize=None, else SAS7BDATReader
- or XportReader
Differences from pandas
This operation has no known divergences from the pandas API.
- filepath_or_buffer (str, path object, or file-like object) – String, path object (implementing
-
apache_beam.dataframe.io.
read_spss
(path, *args, **kwargs)¶ Load an SPSS file from the file path, returning a DataFrame.
New in version 0.25.0.
Parameters: Returns: Return type: Differences from pandas
This operation has no known divergences from the pandas API.
-
apache_beam.dataframe.io.
read_stata
(path, *args, **kwargs)¶ Read Stata file into DataFrame.
Parameters: - filepath_or_buffer (str, path object or file-like object) –
Any valid string path is acceptable. The string could be a URL. Valid URL schemes include http, ftp, s3, and file. For file URLs, a host is expected. A local file could be:
file://localhost/path/to/table.dta
.If you want to pass in a path object, pandas accepts any
os.PathLike
.By file-like object, we refer to objects with a
read()
method, such as a file handle (e.g. via builtinopen
function) orStringIO
. - convert_dates (bool, default True) – Convert date variables to DeferredDataFrame time values.
- convert_categoricals (bool, default True) – Read value labels and convert columns to Categorical/Factor variables.
- index_col (str, optional) – Column to set as index.
- convert_missing (bool, default False) – Flag indicating whether to convert missing values to their Stata representations. If False, missing values are replaced with nan. If True, columns containing missing values are returned with object data types and missing values are represented by StataMissingValue objects.
- preserve_dtypes (bool, default True) – Preserve Stata datatypes. If False, numeric data are upcast to pandas default types for foreign data (float64 or int64).
- columns (list or None) – Columns to retain. Columns will be returned in the given order. None returns all columns.
- order_categoricals (bool, default True) – Flag indicating whether converted categorical data are ordered.
- chunksize (int, default None) – Return StataReader object for iterations, returns chunks with given number of lines.
- iterator (bool, default False) – Return StataReader object.
- compression (str or dict, default 'infer') –
For on-the-fly decompression of on-disk data. If ‘infer’ and ‘filepath_or_buffer’ is path-like, then detect compression from the following extensions: ‘.gz’, ‘.bz2’, ‘.zip’, ‘.xz’, ‘.zst’, ‘.tar’, ‘.tar.gz’, ‘.tar.xz’ or ‘.tar.bz2’ (otherwise no compression). If using ‘zip’ or ‘tar’, the ZIP file must contain only one data file to be read in. Set to
None
for no decompression. Can also be a dict with key'method'
set to one of {'zip'
,'gzip'
,'bz2'
,'zstd'
,'tar'
} and other key-value pairs are forwarded tozipfile.ZipFile
,gzip.GzipFile
,bz2.BZ2File
,zstandard.ZstdDecompressor
ortarfile.TarFile
, respectively. As an example, the following could be passed for Zstandard decompression using a custom compression dictionary:compression={'method': 'zstd', 'dict_data': my_compression_dict}
.New in version 1.5.0: Added support for .tar files.
- storage_options (dict, optional) –
Extra options that make sense for a particular storage connection, e.g. host, port, username, password, etc. For HTTP(S) URLs the key-value pairs are forwarded to
urllib.request.Request
as header options. For other URLs (e.g. starting with “s3://”, and “gcs://”) the key-value pairs are forwarded tofsspec.open
. Please seefsspec
andurllib
for more details, and for more examples on storage options refer here.
Returns: Return type: DeferredDataFrame or StataReader
Differences from pandas
This operation has no known divergences from the pandas API.
See also
io.stata.StataReader()
- Low-level reader for Stata data files.
DeferredDataFrame.to_stata()
- Export Stata data files.
Notes
Categorical variables read through an iterator may not have the same categories and dtype. This occurs when a variable stored in a DTA file is associated to an incomplete set of value labels that only label a strict subset of the values.
Examples
NOTE: These examples are pulled directly from the pandas documentation for convenience. Usage of the Beam DataFrame API will look different because it is a deferred API.
Creating a dummy stata for this example >>> df = pd.DataFrame({'animal': ['falcon', 'parrot', 'falcon', ... 'parrot'], ... 'speed': [350, 18, 361, 15]}) >>> df.to_stata('animals.dta') Read a Stata dta file: >>> df = pd.read_stata('animals.dta') Read a Stata dta file in 10,000 line chunks: >>> values = np.random.randint(0, 10, size=(20_000, 1), dtype="uint8") >>> df = pd.DataFrame(values, columns=["i"]) >>> df.to_stata('filename.dta') >>> itr = pd.read_stata('filename.dta', chunksize=10000) >>> for chunk in itr: ... # Operate on a single chunk, e.g., chunk.mean() ... pass
- filepath_or_buffer (str, path object or file-like object) –
-
apache_beam.dataframe.io.
to_excel
(df, path, *args, **kwargs)¶ Write object to an Excel sheet.
To write a single object to an Excel .xlsx file it is only necessary to specify a target file name. To write to multiple sheets it is necessary to create an ExcelWriter object with a target file name, and specify a sheet in the file to write to.
Multiple sheets may be written to by specifying unique sheet_name. With all data written to the file it is necessary to save the changes. Note that creating an ExcelWriter object with a file name that already exists will result in the contents of the existing file being erased.
Parameters: - excel_writer (path-like, file-like, or ExcelWriter object) – File path or existing ExcelWriter.
- sheet_name (str, default 'Sheet1') – Name of sheet which will contain DeferredDataFrame.
- na_rep (str, default '') – Missing data representation.
- float_format (str, optional) – Format string for floating point numbers. For example
float_format="%.2f"
will format 0.1234 to 0.12. - columns (sequence or list of str, optional) – Columns to write.
- header (bool or list of str, default True) – Write out the column names. If a list of string is given it is assumed to be aliases for the column names.
- index (bool, default True) – Write row names (index).
- index_label (str or sequence, optional) – Column label for index column(s) if desired. If not specified, and header and index are True, then the index names are used. A sequence should be given if the DeferredDataFrame uses MultiIndex.
- startrow (int, default 0) – Upper left cell row to dump data frame.
- startcol (int, default 0) – Upper left cell column to dump data frame.
- engine (str, optional) –
Write engine to use, ‘openpyxl’ or ‘xlsxwriter’. You can also set this via the options
io.excel.xlsx.writer
,io.excel.xls.writer
, andio.excel.xlsm.writer
.Deprecated since version 1.2.0: As the xlwt package is no longer maintained, the
xlwt
engine will be removed in a future version of pandas. - merge_cells (bool, default True) – Write MultiIndex and Hierarchical Rows as merged cells.
- encoding (str, optional) –
Encoding of the resulting excel file. Only necessary for xlwt, other writers support unicode natively.
Deprecated since version 1.5.0: This keyword was not used.
- inf_rep (str, default 'inf') – Representation for infinity (there is no native representation for infinity in Excel).
- verbose (bool, default True) –
Display more information in the error logs.
Deprecated since version 1.5.0: This keyword was not used.
- freeze_panes (tuple of int (length 2), optional) – Specifies the one-based bottommost row and rightmost column that is to be frozen.
- storage_options (dict, optional) –
Extra options that make sense for a particular storage connection, e.g. host, port, username, password, etc. For HTTP(S) URLs the key-value pairs are forwarded to
urllib.request.Request
as header options. For other URLs (e.g. starting with “s3://”, and “gcs://”) the key-value pairs are forwarded tofsspec.open
. Please seefsspec
andurllib
for more details, and for more examples on storage options refer here.New in version 1.2.0.
Differences from pandas
This operation has no known divergences from the pandas API.
See also
to_csv()
- Write DeferredDataFrame to a comma-separated values (csv) file.
ExcelWriter()
- Class for writing DeferredDataFrame objects into excel sheets.
read_excel()
- Read an Excel file into a pandas DeferredDataFrame.
read_csv()
- Read a comma-separated values (csv) file into DeferredDataFrame.
io.formats.style.Styler.to_excel()
- Add styles to Excel sheet.
Notes
For compatibility with
to_csv()
, to_excel serializes lists and dicts to strings before writing.Once a workbook has been saved it is not possible to write further data without rewriting the whole workbook.
Examples
NOTE: These examples are pulled directly from the pandas documentation for convenience. Usage of the Beam DataFrame API will look different because it is a deferred API.
Create, write to and save a workbook: >>> df1 = pd.DataFrame([['a', 'b'], ['c', 'd']], ... index=['row 1', 'row 2'], ... columns=['col 1', 'col 2']) >>> df1.to_excel("output.xlsx") To specify the sheet name: >>> df1.to_excel("output.xlsx", ... sheet_name='Sheet_name_1') If you wish to write to more than one sheet in the workbook, it is necessary to specify an ExcelWriter object: >>> df2 = df1.copy() >>> with pd.ExcelWriter('output.xlsx') as writer: ... df1.to_excel(writer, sheet_name='Sheet_name_1') ... df2.to_excel(writer, sheet_name='Sheet_name_2') ExcelWriter can also be used to append to an existing Excel file: >>> with pd.ExcelWriter('output.xlsx', ... mode='a') as writer: ... df.to_excel(writer, sheet_name='Sheet_name_3') To set the library that is used to write the Excel file, you can pass the `engine` keyword (the default engine is automatically chosen depending on the file extension): >>> df1.to_excel('output1.xlsx', engine='xlsxwriter')
-
apache_beam.dataframe.io.
to_feather
(df, path, *args, **kwargs)¶ Write a DataFrame to the binary Feather format.
Parameters: - path (str, path object, file-like object) – String, path object (implementing
os.PathLike[str]
), or file-like object implementing a binarywrite()
function. If a string or a path, it will be used as Root Directory path when writing a partitioned dataset. - **kwargs –
Additional keywords passed to
pyarrow.feather.write_feather()
. Starting with pyarrow 0.17, this includes the compression, compression_level, chunksize and version keywords.New in version 1.1.0.
Differences from pandas
This operation has no known divergences from the pandas API.
Notes
This function writes the dataframe as a feather file. Requires a default index. For saving the DeferredDataFrame with your custom index use a method that supports custom indices e.g. to_parquet.
- path (str, path object, file-like object) – String, path object (implementing
-
apache_beam.dataframe.io.
to_parquet
(df, path, *args, **kwargs)¶ Write a DataFrame to the binary parquet format.
This function writes the dataframe as a parquet file. You can choose different parquet backends, and have the option of compression. See the user guide for more details.
Parameters: - path (str, path object, file-like object, or None, default None) –
String, path object (implementing
os.PathLike[str]
), or file-like object implementing a binarywrite()
function. If None, the result is returned as bytes. If a string or path, it will be used as Root Directory path when writing a partitioned dataset.Changed in version 1.2.0.
Previously this was “fname”
- engine ({'auto', 'pyarrow', 'fastparquet'}, default 'auto') – Parquet library to use. If ‘auto’, then the option
io.parquet.engine
is used. The defaultio.parquet.engine
behavior is to try ‘pyarrow’, falling back to ‘fastparquet’ if ‘pyarrow’ is unavailable. - compression ({'snappy', 'gzip', 'brotli', None}, default 'snappy') – Name of the compression to use. Use
None
for no compression. - index (bool, default None) – If
True
, include the dataframe’s index(es) in the file output. IfFalse
, they will not be written to the file. IfNone
, similar toTrue
the dataframe’s index(es) will be saved. However, instead of being saved as values, the RangeIndex will be stored as a range in the metadata so it doesn’t require much space and is faster. Other indexes will be included as columns in the file output. - partition_cols (list, optional, default None) – Column names by which to partition the dataset. Columns are partitioned in the order they are given. Must be None if path is not a string.
- storage_options (dict, optional) –
Extra options that make sense for a particular storage connection, e.g. host, port, username, password, etc. For HTTP(S) URLs the key-value pairs are forwarded to
urllib.request.Request
as header options. For other URLs (e.g. starting with “s3://”, and “gcs://”) the key-value pairs are forwarded tofsspec.open
. Please seefsspec
andurllib
for more details, and for more examples on storage options refer here.New in version 1.2.0.
- **kwargs – Additional arguments passed to the parquet library. See pandas io for more details.
Returns: Return type: bytes if no path argument is provided else None
Differences from pandas
This operation has no known divergences from the pandas API.
See also
read_parquet()
- Read a parquet file.
DeferredDataFrame.to_orc()
- Write an orc file.
DeferredDataFrame.to_csv()
- Write a csv file.
DeferredDataFrame.to_sql()
- Write to a sql table.
DeferredDataFrame.to_hdf()
- Write to hdf.
Notes
This function requires either the fastparquet or pyarrow library.
Examples
NOTE: These examples are pulled directly from the pandas documentation for convenience. Usage of the Beam DataFrame API will look different because it is a deferred API.
>>> df = pd.DataFrame(data={'col1': [1, 2], 'col2': [3, 4]}) >>> df.to_parquet('df.parquet.gzip', ... compression='gzip') >>> pd.read_parquet('df.parquet.gzip') col1 col2 0 1 3 1 2 4 If you want to get a buffer to the parquet content you can use a io.BytesIO object, as long as you don't use partition_cols, which creates multiple files. >>> import io >>> f = io.BytesIO() >>> df.to_parquet(f) >>> f.seek(0) 0 >>> content = f.read()
- path (str, path object, file-like object, or None, default None) –
-
apache_beam.dataframe.io.
to_stata
(df, path, *args, **kwargs)¶ Export DataFrame object to Stata dta format.
Writes the DataFrame to a Stata dataset file. “dta” files contain a Stata dataset.
Parameters: - path (str, path object, or buffer) –
String, path object (implementing
os.PathLike[str]
), or file-like object implementing a binarywrite()
function.Changed in version 1.0.0.
Previously this was “fname”
- convert_dates (dict) – Dictionary mapping columns containing datetime types to stata internal format to use when writing the dates. Options are ‘tc’, ‘td’, ‘tm’, ‘tw’, ‘th’, ‘tq’, ‘ty’. Column can be either an integer or a name. Datetime columns that do not have a conversion type specified will be converted to ‘tc’. Raises NotImplementedError if a datetime column has timezone information.
- write_index (bool) – Write the index to Stata dataset.
- byteorder (str) – Can be “>”, “<”, “little”, or “big”. default is sys.byteorder.
- time_stamp (datetime) – A datetime to use as file creation date. Default is the current time.
- data_label (str, optional) – A label for the data set. Must be 80 characters or smaller.
- variable_labels (dict) – Dictionary containing columns as keys and variable labels as values. Each label must be 80 characters or smaller.
- version ({114, 117, 118, 119, None}, default 114) –
Version to use in the output dta file. Set to None to let pandas decide between 118 or 119 formats depending on the number of columns in the frame. pandas Version 114 can be read by Stata 10 and later. pandas Version 117 can be read by Stata 13 or later. pandas Version 118 is supported in Stata 14 and later. pandas Version 119 is supported in Stata 15 and later. pandas Version 114 limits string variables to 244 characters or fewer while versions 117 and later allow strings with lengths up to 2,000,000 characters. Versions 118 and 119 support Unicode characters, and pandas version 119 supports more than 32,767 variables.
pandas Version 119 should usually only be used when the number of variables exceeds the capacity of dta format 118. Exporting smaller datasets in format 119 may have unintended consequences, and, as of November 2020, Stata SE cannot read pandas version 119 files.
Changed in version 1.0.0: Added support for formats 118 and 119.
- convert_strl (list, optional) – List of column names to convert to string columns to Stata StrL format. Only available if version is 117. Storing strings in the StrL format can produce smaller dta files if strings have more than 8 characters and values are repeated.
- compression (str or dict, default 'infer') –
For on-the-fly compression of the output data. If ‘infer’ and ‘path’ is path-like, then detect compression from the following extensions: ‘.gz’, ‘.bz2’, ‘.zip’, ‘.xz’, ‘.zst’, ‘.tar’, ‘.tar.gz’, ‘.tar.xz’ or ‘.tar.bz2’ (otherwise no compression). Set to
None
for no compression. Can also be a dict with key'method'
set to one of {'zip'
,'gzip'
,'bz2'
,'zstd'
,'tar'
} and other key-value pairs are forwarded tozipfile.ZipFile
,gzip.GzipFile
,bz2.BZ2File
,zstandard.ZstdCompressor
ortarfile.TarFile
, respectively. As an example, the following could be passed for faster compression and to create a reproducible gzip archive:compression={'method': 'gzip', 'compresslevel': 1, 'mtime': 1}
.New in version 1.5.0: Added support for .tar files.
New in version 1.1.0.
Changed in version 1.4.0: Zstandard support.
- storage_options (dict, optional) –
Extra options that make sense for a particular storage connection, e.g. host, port, username, password, etc. For HTTP(S) URLs the key-value pairs are forwarded to
urllib.request.Request
as header options. For other URLs (e.g. starting with “s3://”, and “gcs://”) the key-value pairs are forwarded tofsspec.open
. Please seefsspec
andurllib
for more details, and for more examples on storage options refer here.New in version 1.2.0.
- value_labels (dict of dicts) –
Dictionary containing columns as keys and dictionaries of column value to labels as values. Labels for a single variable must be 32,000 characters or smaller.
New in version 1.4.0.
Raises: NotImplementedError
– * If datetimes contain timezone information * Column dtype is not representable in StataValueError
– * Columns listed in convert_dates are neither datetime64[ns]or datetime.datetime
- Column listed in convert_dates is not in DeferredDataFrame
- Categorical label contains more than 32,000 characters
Differences from pandas
This operation has no known divergences from the pandas API.
See also
read_stata()
- Import Stata data files.
io.stata.StataWriter()
- Low-level writer for Stata data files.
io.stata.StataWriter117()
- Low-level writer for pandas version 117 files.
Examples
NOTE: These examples are pulled directly from the pandas documentation for convenience. Usage of the Beam DataFrame API will look different because it is a deferred API.
>>> df = pd.DataFrame({'animal': ['falcon', 'parrot', 'falcon', ... 'parrot'], ... 'speed': [350, 18, 361, 15]}) >>> df.to_stata('animals.dta')
- path (str, path object, or buffer) –