Function consume

Lib/test/test_zipfile/_path/_itertools.py:47–79

Advance *iterable* by *n* steps. If *n* is ``None``, consume it entirely. Efficiently exhausts an iterator without returning values. Defaults to consuming the whole iterator, but an optional second argument may be provided to limit consumption. >>> i = (x for x in range(10))

(iterator, n=None)

# from more_itertools v9.0.0
def consume(iterator, n=None):
    """Advance *iterable* by *n* steps. If *n* is ``None``, consume it
    entirely.
    Efficiently exhausts an iterator without returning values. Defaults to
    consuming the whole iterator, but an optional second argument may be
    provided to limit consumption.
        >>> i = (x for x in range(10))
        >>> next(i)
        0
        >>> consume(i, 3)
        >>> next(i)
        4
        >>> consume(i)
        >>> next(i)
        Traceback (most recent call last):
          File "<stdin>", line 1, in <module>
        StopIteration
    If the iterator has fewer items remaining than the provided limit, the
    whole iterator will be consumed.
        >>> i = (x for x in range(3))
        >>> consume(i, 5)
        >>> next(i)
        Traceback (most recent call last):
          File "<stdin>", line 1, in <module>
        StopIteration
    """
    # Use functions that consume iterators at C speed.
    if n is None:
        # feed the entire iterator into a zero-length deque
        deque(iterator, maxlen=0)
    else:
        # advance to the empty slice starting at position n
        next(islice(iterator, n, n), None)