Generates pairs where the first element is an item from the iterable source and the second element is a boolean flag indicating if it is the last item in the sequence. #Python #iterate

iter_islast.py

def iter_islast(iterable):
    """
    iter_islast(iterable) -> generates (item, islast) pairs

    Generates pairs where the first element is an item from the iterable
    source and the second element is a boolean flag indicating if it is
    the last item in the sequence.

    Referenced from
    `here <http://code.activestate.com/recipes/392015-finding-the-last-item-in-a-loop/>`_.
    .. doctest::

        >>> for n, islast in iter_islast(range(4)):
        ...   if islast:
        ...       print "last but not least:",
        ...   print n
        ...
        0
        1
        2
        last but not least: 3

        >>> list(iter_islast(''))
        []
        >>> list(iter_islast('1'))
        [('1', True)]
        >>> list(iter_islast('12'))
        [('1', False), ('2', True)]
        >>> list(iter_islast('123'))
        [('1', False), ('2', False), ('3', True)]
    """

    it = iter(iterable)
    prev = it.next()
    for item in it:
        yield prev, False
        prev = item
    yield prev, True