Python 将列表n等分

将 python 列表约n等分（大多数情况下是无法分的正好的，除非 n % ncut==0）

自己懒得写，google了半天，大多数不是有错就是从有错的地方抄来的，血压拉满。于是自己写了两种，时间复杂度均为O(n)

如果有更好的办法或者有错误可以分享并指正。

顺便吐槽一句python的数据结构实现真的是太令人头疼了。

def partition_size(ls: list, size):
    """
    Returns a new list with elements
    of which is a list of certain size.
        >>> partition_size([1, 2, 3, 4], 3)
        [[1, 2, 3], [4]]

    :param ls:
    :param size:
    :return: list cut by size
    """
    if size <= 0:
        return ls
    return [ls[i:i + size] for i in range(0, len(ls), size)]


def partition_cut(ls: list, ncut):
    """
    Returns a new list with elements
    of which is a list of certain size.
        >>> partition_cut([1, 2, 3, 4, 5], 3)
        [[1, 2], [3, 4], [5]]

    :param ls:
    :param n:
    :return: list has been cut
    """
    n = len(ls)
    if n <= 1 or ncut <= 1:
        return ls

    res = []
    ncut_r = ncut
    n_r = n
    while ncut_r > 0:
        if n_r % ncut_r == 0:
            dist = int(n_r / ncut_r)
            for _ in range(ncut_r):
                next = n - n_r + dist
                res.insert(len(res), ls[n - n_r:next])
                n_r -= dist
            break
        else:
            dist = ceil(n_r / ncut_r)
            res.insert(len(res), ls[n - n_r:n - n_r + dist])
            ncut_r -= 1
            n_r -= dist
            continue

    return res


def partition_cut2(ls: list, ncut):
    """
    Returns a new list with elements
    of which is a list of certain size.
        >>> partition_cut([1, 2, 3, 4, 5], 3)
        [[1, 4], [2, 5], [3]]

    :param ls:
    :param n:
    :return: list has been cut
    """
    n = len(ls)
    if n <= 1 or ncut <= 1:
        return ls

    res = [[] for _ in range(ncut)]
    for i in range(n):
        idx = i % ncut
        res[idx].append(ls[i])

    return res


if __name__ == '__main__':
    l1 = list(range(1, 6, 1))

    # for i in range(0, len(l1)):
    #    print('cut {} : {}'.format(i, partition_size(l1, i)))

    for i in range(0, len(l1)):
        print('cut {} : {}'.format(i, partition_cut(l1, i)))
    print('finished')

    for i in range(0, len(l1)):
        print('cut {} : {}'.format(i, partition_cut2(l1, i)))
    print('finished')