def zip(datastreams: List[Datastream]) -> Datastream[Tuple]:
'''
Zip multiple datastreams together so that all combinations of examples
are possible (i.e. the product) creating tuples like
``(example1, example2, ...)``. The samples are drawn independently
from each underlying datastream.
'''
return Datastream(
Dataset.combine([datastream.dataset
for datastream in datastreams]),
ZipSampler(*zip(*[(datastream.sampler, datastream.dataset)
for datastream in datastreams])),
)
def test_combine_concat_merge():
dataset = Dataset.concat([
Dataset.zip([
Dataset.from_subscriptable([1]),
Dataset.from_subscriptable([2]),
]),
Dataset.combine([
Dataset.from_subscriptable([3, 3]),
Dataset.from_subscriptable([4, 4, 4]),
]),
])
datastream = Datastream.merge([
Datastream(dataset),
Datastream(
Dataset.zip([
Dataset.from_subscriptable([5]),
Dataset.from_subscriptable([6]),
])),
])
assert len(list(datastream)) == 2