Pandas DataFrame: to_hdf() function

Last update on August 19 2022 21:50:51 (UTC/GMT +8 hours)

DataFrame - to_hdf() function

The to_hdf() function is used to write the contained data to an HDF5 file using HDFStore.

Syntax:

DataFrame.to_hdf(self, path_or_buf, key, **kwargs)

Parameters:

Name	Description	Type/Default Value	Required / Optional
path_or_buf	File path or HDFStore object.	str or pandas.HDFStore	Required
key	Identifier for the group in the store.	str	Required
mode	Mode to open file: 'w': write, a new file is created (an existing file with the same name would be deleted). 'a': append, an existing file is opened for reading and writing, and if the file does not exist it is created. ‘r+’: similar to 'a', but the file must already exist.	{'a', 'w', 'r+'} Default Value: ‘a’	Required
format	Possible values: 'fixed': Fixed format. Fast writing/reading. Not-appendable, nor searchable. 'table': Table format. Write as a PyTables Table structure which may perform worse but allow more flexible operations like searching / selecting subsets of the data.	{‘fixed’, ‘table’} Default Value: ‘fixed’	Required
append	For Table formats, append the input data to the existing.	bool Default Value: False	Required
data_columns	List of columns to create as indexed data columns for on-disk queries, or True to use all columns. By default only the axes of the object are indexed.	list of columns Default Value: True	Optional
complevel	Specifies a compression level for data. A value of 0 disables compression.	{0-9}	Optional
complib	Specifies the compression library to be used. As of v0.20.2 these additional compressors for Blosc are supported (default if no compressor specified: ‘blosc:blosclz’): {‘blosc:blosclz’, ‘blosc:lz4’, ‘blosc:lz4hc’, ‘blosc:snappy’, ‘blosc:zlib’, ‘blosc:zstd’}. Specifying a compression library which is not available issues a ValueError.	{‘zlib’, ‘lzo’, ‘bzip2’, ‘blosc’} Default Value: ‘zlib’	Required
fletcher32	If applying compression use the fletcher32 checksum.	bool Default Value: False	Required
dropna	If true, ALL nan rows will not be written to store.	bool Default Value: False	Required
errors	Specifies how encoding and decoding errors are to be handled. See the errors argument for open() for a full list of options.	str Default Value: ‘strict’	Optional

Example:

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