pandas.DataFrame.to_hdf

Write the contained data to an HDF5 file using HDFStore.

Hierarchical Data Format (HDF) is self-describing, allowing an application to interpret the structure and contents of a file with no outside information. One HDF file can hold a mix of related objects which can be accessed as a group or as individual objects.

In order to add another DataFrame or Series to an existing HDF file please use append mode and a different a key.

For more information see the user guide.

param path_or_buf

str or pandas.HDFStore

File path or HDFStore object.

param key

str

Identifier for the group in the store.

param mode

{‘a’, ‘w’, ‘r+’}, default ‘a’

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.

param format

{‘fixed’, ‘table’}, default ‘fixed’

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.

param append

bool, default False

For Table formats, append the input data to the existing.

param data_columns

list of columns or True, optional

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. See Query via data columns. Applicable only to format=’table’.

param complevel

{0-9}, optional

Specifies a compression level for data. A value of 0 disables compression.

param complib

{‘zlib’, ‘lzo’, ‘bzip2’, ‘blosc’}, default ‘zlib’

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.

param fletcher32

bool, default False

If applying compression use the fletcher32 checksum.

param dropna

bool, default False

If true, ALL nan rows will not be written to store.

param 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.

Warning

This feature is currently unsupported by Intel Scalable Dataframe Compiler