pyspark.sql.datasource.DataSourceReader.read#

abstract DataSourceReader.read(partition)[source]#

Generates data for a given partition and returns an iterator of tuples or rows.

This method is invoked once per partition to read the data. Implementing this method is required for readable data sources. You can initialize any non-serializable resources required for reading data from the data source within this method.

Parameters

partitionobject: The partition to read. It must be one of the partition values returned by DataSourceReader.partitions().

Returns

iterator of tuples or PyArrow’s RecordBatch: An iterator of tuples or rows. Each tuple or row will be converted to a row in the final DataFrame. It can also return an iterator of PyArrow’s RecordBatch if the data source supports it.

Examples

Yields a list of tuples:

>>> def read(self, partition: InputPartition):
...     yield (partition.value, 0)
...     yield (partition.value, 1)

Yields a list of rows:

>>> def read(self, partition: InputPartition):
...     yield Row(partition=partition.value, value=0)
...     yield Row(partition=partition.value, value=1)