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# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
from itertools import islice
class ChunkingError(Exception):
pass
def split_evenly(n, chunks):
"""Split an integer into evenly distributed list
>>> split_evenly(7, 3)
[3, 2, 2]
>>> split_evenly(12, 3)
[4, 4, 4]
>>> split_evenly(35, 10)
[4, 4, 4, 4, 4, 3, 3, 3, 3, 3]
>>> split_evenly(1, 2)
Traceback (most recent call last):
...
ChunkingError: Number of chunks is greater than number
"""
if n < chunks:
raise ChunkingError("Number of chunks is greater than number")
if n % chunks == 0:
# Either we can evenly split or only 1 chunk left
return [n // chunks] * chunks
# otherwise the current chunk should be a bit larger
max_size = n // chunks + 1
return [max_size] + split_evenly(n - max_size, chunks - 1)
def chunkify(things, this_chunk, chunks):
if this_chunk > chunks:
raise ChunkingError("this_chunk is greater than total chunks")
dist = split_evenly(len(things), chunks)
start = sum(dist[:this_chunk-1])
end = start + dist[this_chunk-1]
try:
return things[start:end]
except TypeError:
return islice(things, start, end)