tf.data.experimental.group_by_reducer

A transformation that groups elements and performs a reduction.

This transformation maps element of a dataset to a key using key_func and groups the elements by key. The reducer is used to process each group; its init_func is used to initialize state for each group when it is created, the reduce_func is used to update the state every time an element is mapped to the matching group, and the finalize_func is used to map the final state to an output value.

key_func A function mapping a nested structure of tensors (having shapes and types defined by self.output_shapes and self.output_types) to a scalar tf.int64 tensor.
reducer An instance of Reducer, which captures the reduction logic using the init_func, reduce_func, and finalize_func functions.

A Dataset transformation function, which can be passed to tf.data.Dataset.apply.