tf.contrib.data.group_by_window(
key_func,
reduce_func,
window_size=None,
window_size_func=None
)
Defined in tensorflow/contrib/data/python/ops/grouping.py
.
A transformation that groups windows of elements by key and reduces them. (deprecated)
This transformation maps each consecutive element in a dataset to a key
using key_func
and groups the elements by key. It then applies
reduce_func
to at most window_size_func(key)
elements matching the same
key. All except the final window for each key will contain
window_size_func(key)
elements; the final window may be smaller.
You may provide either a constant window_size
or a window size determined by
the key through window_size_func
.
Args:
key_func
: A function mapping a nested structure of tensors (having shapes and types defined byself.output_shapes
andself.output_types
) to a scalartf.int64
tensor.reduce_func
: A function mapping a key and a dataset of up towindow_size
consecutive elements matching that key to another dataset.window_size
: Atf.int64
scalartf.Tensor
, representing the number of consecutive elements matching the same key to combine in a single batch, which will be passed toreduce_func
. Mutually exclusive withwindow_size_func
.window_size_func
: A function mapping a key to atf.int64
scalartf.Tensor
, representing the number of consecutive elements matching the same key to combine in a single batch, which will be passed toreduce_func
. Mutually exclusive withwindow_size
.
Returns:
A Dataset
transformation function, which can be passed to
tf.data.Dataset.apply
.
Raises:
ValueError
: if neither or both of {window_size
,window_size_func
} are passed.