Attention

June 2024 Status Update: Removing DataPipes and DataLoader V2

We are re-focusing the torchdata repo to be an iterative enhancement of torch.utils.data.DataLoader. We do not plan on continuing development or maintaining the [DataPipes] and [DataLoaderV2] solutions, and they will be removed from the torchdata repo. We’ll also be revisiting the DataPipes references in pytorch/pytorch. In release torchdata==0.8.0 (July 2024) they will be marked as deprecated, and in 0.9.0 (Oct 2024) they will be deleted. Existing users are advised to pin to torchdata==0.8.0 or an older version until they are able to migrate away. Subsequent releases will not include DataPipes or DataLoaderV2. Please reach out if you suggestions or comments (please use this issue for feedback)

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]