Python split list into n chunks

Question

I know this question has been covered many times but my requirement is different.

I have a list like: range(1, 26). I want to divide this list into a fi

Answer 1

If you want to have the chunks as evenly sized as possible:

def chunk_ranges(items: int, chunks: int) -> List[Tuple[int, int]]:
    """
    Split the items by best effort into equally-sized chunks.
    
    If there are fewer items than chunks, each chunk contains an item and 
    there are fewer returned chunk indices than the argument `chunks`.

    :param items: number of items in the batch.
    :param chunks: number of chunks
    :return: list of (chunk begin inclusive, chunk end exclusive)
    """
    assert chunks > 0, \
        "Unexpected non-positive chunk count: {}".format(chunks)

    result = []  # type: List[Tuple[int, int]]
    if items <= chunks:
        for i in range(0, items):
            result.append((i, i + 1))
        return result

    chunk_size, extras = divmod(items, chunks)

    start = 0
    for i in range(0, chunks):
        if i < extras:
            end = start + chunk_size + 1
        else:
            end = start + chunk_size

        result.append((start, end))
        start = end

    return result

Test case:

def test_chunk_ranges(self):
    self.assertListEqual(chunk_ranges(items=8, chunks=1),
                         [(0, 8)])

    self.assertListEqual(chunk_ranges(items=8, chunks=2),
                         [(0, 4), (4, 8)])

    self.assertListEqual(chunk_ranges(items=8, chunks=3),
                         [(0, 3), (3, 6), (6, 8)])

    self.assertListEqual(chunk_ranges(items=8, chunks=5),
                         [(0, 2), (2, 4), (4, 6), (6, 7), (7, 8)])

    self.assertListEqual(chunk_ranges(items=8, chunks=6),
                         [(0, 2), (2, 4), (4, 5), (5, 6), (6, 7), (7, 8)])

    self.assertListEqual(
        chunk_ranges(items=8, chunks=7),
        [(0, 2), (2, 3), (3, 4), (4, 5), (5, 6), (6, 7), (7, 8)])

    self.assertListEqual(
        chunk_ranges(items=8, chunks=9),
        [(0, 1), (1, 2), (2, 3), (3, 4), (4, 5), (5, 6), (6, 7), (7, 8)])