collect_ranges.py

def collect_ranges(s):
    """
    Returns a generator of tuples of consecutive numbers found in the input.

    >>> list(collect_ranges([]))
    []
    >>> list(collect_ranges([1]))
    [(1, 1)]
    >>> list(collect_ranges([1,2,3]))
    [(1, 3)]
    >>> list(collect_ranges([1,5,7,9]))
    [(1, 1), (5, 5), (7, 7), (9, 9)]
    >>> list(collect_ranges([0,1,2,3,7,8,9,12,13,14,23]))
    [(0, 3), (7, 9), (12, 14), (23, 23)]
    """
    if len(s) == 0:
        pass
    elif len(s) == 1:
        yield (s[0], s[0])
    else:
        start = end = s.pop(0)
        while len(s):
            temp = s.pop(0)
            if temp > end + 1:
                yield (start, end)
                start = end = temp
            else:
                end = temp
        yield (start, end)


if __name__ == '__main__':

    # Tests in docstrings
    import doctest
    doctest.testmod()

    # Fuzz tests
    import random
    for i in range(100):
        s = [random.randrange(100) for x in range(random.randrange(100))]
        print list(collect_ranges(sorted(s))), sorted(s)