49 lines
1.6 KiB
Python
49 lines
1.6 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2014-2016 OpenMarket Ltd
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# Copyright 2020 The Matrix.org Foundation C.I.C.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from itertools import islice
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from typing import Iterable, Iterator, Sequence, Tuple, TypeVar
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T = TypeVar("T")
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def batch_iter(iterable: Iterable[T], size: int) -> Iterator[Tuple[T]]:
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"""batch an iterable up into tuples with a maximum size
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Args:
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iterable (iterable): the iterable to slice
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size (int): the maximum batch size
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Returns:
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an iterator over the chunks
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"""
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# make sure we can deal with iterables like lists too
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sourceiter = iter(iterable)
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# call islice until it returns an empty tuple
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return iter(lambda: tuple(islice(sourceiter, size)), ())
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ISeq = TypeVar("ISeq", bound=Sequence, covariant=True)
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def chunk_seq(iseq: ISeq, maxlen: int) -> Iterable[ISeq]:
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"""Split the given sequence into chunks of the given size
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The last chunk may be shorter than the given size.
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If the input is empty, no chunks are returned.
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"""
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return (iseq[i : i + maxlen] for i in range(0, len(iseq), maxlen))
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