pyarrow.dataset.DirectoryPartitioning

class pyarrow.dataset.DirectoryPartitioning

Bases: pyarrow._dataset.Partitioning

A Partitioning based on a specified Schema.

The DirectoryPartitioning expects one segment in the file path for each field in the schema (all fields are required to be present). For example given schema<year:int16, month:int8> the path “/2009/11” would be parsed to (“year”_ == 2009 and “month”_ == 11).

Parameters

schema (Schema) – The schema that describes the partitions present in the file path.

Returns

DirectoryPartitioning

Examples

>>> from pyarrow.dataset import DirectoryPartitioning
>>> partition = DirectoryPartitioning(
...     pa.schema([("year", pa.int16()), ("month", pa.int8())]))
>>> print(partitioning.parse("/2009/11"))
((year == 2009:int16) and (month == 11:int8))

__init__(*args, **kwargs)

Initialize self. See help(type(self)) for accurate signature.

Methods

__init__(*args, **kwargs)	Initialize self.
discover	Discover a DirectoryPartitioning.
parse

Attributes

schema

The arrow Schema attached to the partitioning.

static discover()

Discover a DirectoryPartitioning.

Parameters

• field_names (list of str) – The names to associate with the values from the subdirectory names.

• max_partition_dictionary_size (int or None, default 0) – The maximum number of unique values to consider for dictionary encoding. By default no field will be inferred as dictionary encoded. If None is provided dictionary encoding will be used for every string field.

Returns

DirectoryPartitioningFactory – To be used in the FileSystemFactoryOptions.

parse()

schema

The arrow Schema attached to the partitioning.