Itertools.islice: taking part of a stream without a full list

Useful to know

itertools.islice() selects part of an iterable without necessarily copying every value. list(islice(range(100), 3)) gives [0, 1, 2]. [1]

With a one-pass iterator, values read have been consumed. This matters during sequential imports: another iteration does not automatically restart the source. Lazy processing avoids intermediate results but does not itself define how the source can be replayed.