vig_itertools.py

def accumulate_with_remainder(xs):
    """implements accumulate while also returning the remainder

    >>> accumulate_with_remainder([1,2,3])
    [
        ([], [1,2,3]),
        ([1], [2,3]),
        ([1,2], [3]),
        ([1,2,3], [])
    ]
    
    :param xs: list to accumulate
    :type xs: list
    
    :returns: list of (accumulated elements, remaining elements)
    :rtype: list of (iterable, iterable)
    """

    return [split_at(i, xs) for i in range(len(xs)+1)]


def split_at(i, xs):
    """splits xs at i
    
    >>> split_at(2, [1, 2, 3, 4, 5])
    ([1, 2, 3], [4, 5])

    :param i: index to split at
    :type i: int
    
    :param xs: list to split
    :type xs: list
    
    :returns: first i elements, remaining elements
    :rtype: (list, list)
    """

    return xs[:i], xs[i:]