在我的特殊情况下，我需要填充项目，以重复最后一个元素，直到它达到大小，所以我改变了这个答案，以适应我的需要。

大小为4的输入输出示例:

Input = [1,2,3,4,5,6,7,8]
Output= [[1,2,3,4], [5,6,7,8]]

Input = [[1,2,3,4,5,6,7]]
Output= [[1,2,3,4], [5,6,7,7]]

Input = [1,2,3,4,5]
Output= [[1,2,3,4], [5,5,5,5]]

def chunker(seq, size):
    res = []
    for el in seq:
        res.append(el)
        if len(res) == size:
            yield res
            res = []
    if res:
        res = res + (size - len(res)) * [res[-1]] 
        yield res

关于J.F. Sebastian给出的解决方案:

def chunker(iterable, chunksize):
    return zip(*[iter(iterable)]*chunksize)

它很聪明，但有一个缺点——总是返回元组。如何获得字符串代替? 当然，你可以写“.join(chunker(…))”，但无论如何都要构造临时元组。

你可以通过编写自己的zip来摆脱临时元组，就像这样:

class IteratorExhausted(Exception):
    pass

def translate_StopIteration(iterable, to=IteratorExhausted):
    for i in iterable:
        yield i
    raise to # StopIteration would get ignored because this is generator,
             # but custom exception can leave the generator.

def custom_zip(*iterables, reductor=tuple):
    iterators = tuple(map(translate_StopIteration, iterables))
    while True:
        try:
            yield reductor(next(i) for i in iterators)
        except IteratorExhausted: # when any of iterators get exhausted.
            break

Then

def chunker(data, size, reductor=tuple):
    return custom_zip(*[iter(data)]*size, reductor=reductor)

使用示例:

>>> for i in chunker('12345', 2):
...     print(repr(i))
...
('1', '2')
('3', '4')
>>> for i in chunker('12345', 2, ''.join):
...     print(repr(i))
...
'12'
'34'

import itertools
def chunks(iterable,size):
    it = iter(iterable)
    chunk = tuple(itertools.islice(it,size))
    while chunk:
        yield chunk
        chunk = tuple(itertools.islice(it,size))

# though this will throw ValueError if the length of ints
# isn't a multiple of four:
for x1,x2,x3,x4 in chunks(ints,4):
    foo += x1 + x2 + x3 + x4

for chunk in chunks(ints,4):
    foo += sum(chunk)

另一种方法:

import itertools
def chunks2(iterable,size,filler=None):
    it = itertools.chain(iterable,itertools.repeat(filler,size-1))
    chunk = tuple(itertools.islice(it,size))
    while len(chunk) == size:
        yield chunk
        chunk = tuple(itertools.islice(it,size))

# x2, x3 and x4 could get the value 0 if the length is not
# a multiple of 4.
for x1,x2,x3,x4 in chunks2(ints,4,0):
    foo += x1 + x2 + x3 + x4

这个答案拆分了一个字符串列表，f.ex。达到符合pep8线长的要求:

def split(what, target_length=79):
    '''splits list of strings into sublists, each 
    having string length at most 79'''
    out = [[]]
    while what:
        if len("', '".join(out[-1])) + len(what[0]) < target_length:
            out[-1].append(what.pop(0))
        else:
            if not out[-1]: # string longer than target_length
                out[-1] = [what.pop(0)]
            out.append([])
    return out

使用

>>> split(['deferred_income', 'long_term_incentive', 'restricted_stock_deferred', 'shared_receipt_with_poi', 'loan_advances', 'from_messages', 'other', 'director_fees', 'bonus', 'total_stock_value', 'from_poi_to_this_person', 'from_this_person_to_poi', 'restricted_stock', 'salary', 'total_payments', 'exercised_stock_options'], 75)
[['deferred_income', 'long_term_incentive', 'restricted_stock_deferred'], ['shared_receipt_with_poi', 'loan_advances', 'from_messages', 'other'], ['director_fees', 'bonus', 'total_stock_value', 'from_poi_to_this_person'], ['from_this_person_to_poi', 'restricted_stock', 'salary', 'total_payments'], ['exercised_stock_options']]

另一种方法是使用双参数形式的iter:

from itertools import islice

def group(it, size):
    it = iter(it)
    return iter(lambda: tuple(islice(it, size)), ())

这可以很容易地适应使用填充(这类似于Markus Jarderot的答案):

from itertools import islice, chain, repeat

def group_pad(it, size, pad=None):
    it = chain(iter(it), repeat(pad))
    return iter(lambda: tuple(islice(it, size)), (pad,) * size)

这些甚至可以组合为可选的填充:

_no_pad = object()
def group(it, size, pad=_no_pad):
    if pad == _no_pad:
        it = iter(it)
        sentinel = ()
    else:
        it = chain(iter(it), repeat(pad))
        sentinel = (pad,) * size
    return iter(lambda: tuple(islice(it, size)), sentinel)

我希望通过将迭代器从列表中删除，我不是简单地复制列表的一部分。生成器可以被切片，它们将自动仍然是一个生成器，而列表将被切片成1000个条目的大块，这是较低的效率。

def iter_group(iterable, batch_size:int):
    length = len(iterable)
    start = batch_size*-1
    end = 0
    while(end < length):
        start += batch_size
        end += batch_size
        if type(iterable) == list:
            yield (iterable[i] for i in range(start,min(length-1,end)))
        else:
            yield iterable[start:end]

用法:

items = list(range(1,1251))

for item_group in iter_group(items, 1000):
    for item in item_group:
        print(item)