pyarrow.RecordBatchReader#

class pyarrow.RecordBatchReader#

Bases: _Weakrefable

Base class for reading stream of record batches.

Record batch readers function as iterators of record batches that also provide the schema (without the need to get any batches).

Warning

Do not call this class’s constructor directly, use one of the RecordBatchReader.from_* functions instead.

Notes

To import and export using the Arrow C stream interface, use the _import_from_c and _export_from_c methods. However, keep in mind this interface is intended for expert users.

Examples

>>> import pyarrow as pa
>>> schema = pa.schema([('x', pa.int64())])
>>> def iter_record_batches():
...     for i in range(2):
...         yield pa.RecordBatch.from_arrays([pa.array([1, 2, 3])], schema=schema)
>>> reader = pa.RecordBatchReader.from_batches(schema, iter_record_batches())
>>> print(reader.schema)
x: int64
>>> for batch in reader:
...     print(batch)
pyarrow.RecordBatch
x: int64
----
x: [1,2,3]
pyarrow.RecordBatch
x: int64
----
x: [1,2,3]

__init__(*args, **kwargs)#

Methods

`__init__`(args, *kwargs)
`close`(self)	Release any resources associated with the reader.
`from_batches`(Schema schema, batches)	Create RecordBatchReader from an iterable of batches.
`iter_batches_with_custom_metadata`(self)	Iterate over record batches from the stream along with their custom metadata.
`read_all`(self)	Read all record batches as a pyarrow.Table.
`read_next_batch`(self)	Read next RecordBatch from the stream.
`read_next_batch_with_custom_metadata`(self)	Read next RecordBatch from the stream along with its custom metadata.
`read_pandas`(self, **options)	Read contents of stream to a pandas.DataFrame.

Attributes

schema

Shared schema of the record batches in the stream.

close(self)#: Release any resources associated with the reader.

static from_batches(Schema schema, batches)#

Create RecordBatchReader from an iterable of batches.

Parameters:

schemaSchema: The shared schema of the record batches
batchesIterable[RecordBatch]: The batches that this reader will return.

Returns:

readerRecordBatchReader

iter_batches_with_custom_metadata(self)#

Iterate over record batches from the stream along with their custom metadata.

Yields:

RecordBatchWithMetadata

read_all(self)#

Read all record batches as a pyarrow.Table.

Returns:

Table

read_next_batch(self)#