pyarrow.orc.ORCFile#

class pyarrow.orc.ORCFile(source)[source]#

Bases: object

Reader interface for a single ORC file

Parameters:

sourcestr or pyarrow.NativeFile: Readable source. For passing Python file objects or byte buffers, see pyarrow.io.PythonFileInterface or pyarrow.io.BufferReader.

Methods

`__init__`(source)
`read`([columns])	Read the whole file.
`read_stripe`(n[, columns])	Read a single stripe from the file.

Attributes

`compression`	Compression codec of the file
`compression_size`	Number of bytes to buffer for the compression codec in the file
`content_length`	Length of the data stripes in the file in bytes
`file_footer_length`	The number of compressed bytes in the file footer
`file_length`	The number of bytes in the file
`file_postscript_length`	The number of bytes in the file postscript
`file_version`	Format version of the ORC file, must be 0.11 or 0.12
`metadata`	The file metadata, as an arrow KeyValueMetadata
`nrows`	The number of rows in the file
`nstripe_statistics`	Number of stripe statistics
`nstripes`	The number of stripes in the file
`row_index_stride`	Number of rows per an entry in the row index or 0 if there is no row index
`schema`	The file schema, as an arrow schema
`software_version`	Software instance and version that wrote this file
`stripe_statistics_length`	The number of compressed bytes in the file stripe statistics
`writer`	Name of the writer that wrote this file.
`writer_version`	Version of the writer

property compression_size#: Number of bytes to buffer for the compression codec in the file

property file_footer_length#: The number of compressed bytes in the file footer

property file_postscript_length#: The number of bytes in the file postscript

property file_version#: Format version of the ORC file, must be 0.11 or 0.12

read(columns=None)[source]#

Read the whole file.

Parameters:

columnslist: If not None, only these columns will be read from the file. A column name may be a prefix of a nested field, e.g. ‘a’ will select ‘a.b’, ‘a.c’, and ‘a.d.e’. Output always follows the ordering of the file and not the columns list.

Returns:

read_stripe(n, columns=None)[source]#

Read a single stripe from the file.

Parameters:

nint: The stripe index
columnslist: If not None, only these columns will be read from the stripe. A column name may be a prefix of a nested field, e.g. ‘a’ will select ‘a.b’, ‘a.c’, and ‘a.d.e’

Returns:

property row_index_stride#: Number of rows per an entry in the row index or 0 if there is no row index

property software_version#: Software instance and version that wrote this file

property stripe_statistics_length#: The number of compressed bytes in the file stripe statistics

property writer#: Name of the writer that wrote this file. If the writer is unknown then its Writer ID (a number) is returned