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| -rw-r--r-- | Doc/library/functions.rst | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst index 97f2a38..42e4269 100644 --- a/Doc/library/functions.rst +++ b/Doc/library/functions.rst @@ -1235,11 +1235,18 @@ are always available. They are listed here in alphabetical order. iterable argument, it returns an iterator of 1-tuples. With no arguments, it returns an empty iterator. Equivalent to:: - def zip(*iterables): - # zip('ABCD', 'xy') --> Ax By - iterables = map(iter, iterables) - while iterables: - yield tuple(map(next, iterables)) + def zip(*iterables): + # zip('ABCD', 'xy') --> Ax By + sentinel = object() + iterables = [iter(it) for it in iterables] + while iterables: + result = [] + for it in iterables: + elem = next(it, sentinel) + if elem is sentinel: + return + result.append(elem) + yield tuple(result) The left-to-right evaluation order of the iterables is guaranteed. This makes possible an idiom for clustering a data series into n-length groups |