Mapper

class torchdata.datapipes.map.Mapper(datapipe: ~MapDataPipe, fn: ~Callable = <function default_fn>)

Apply the input function over each item from the source DataPipe (functional name: map).

The function can be any regular Python function or partial object. Lambda function is not recommended as it is not supported by pickle.

Parameters:

• datapipe – Source MapDataPipe

• fn – Function being applied to each item

Example

>>> # xdoctest: +SKIP
>>> from torchdata.datapipes.map import SequenceWrapper, Mapper
>>> def add_one(x):
...     return x + 1
>>> dp = SequenceWrapper(range(10))
>>> map_dp_1 = dp.map(add_one)
>>> list(map_dp_1)
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
>>> map_dp_2 = Mapper(dp, lambda x: x + 1)
>>> list(map_dp_2)
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]