从可迭代对象一次产生多个对象？ [英] Yield multiple objects at a time from an iterable object?

问题描述

如何从可迭代对象一次产生多个项？

How can I yield multiple items at a time from an iterable object?

例如，对于任意长度的序列，我如何遍历项中的序列，每次迭代X个连续项目的组？

For example, with a sequence of arbitrary length, how can I iterate through the items in the sequence, in groups of X consecutive items per iteration?

推荐答案

你的问题有点模糊，但看看 grouper itertools 文档中的食谱。

Your question is a bit vague, but check out the grouper recipe in the itertools documentation.

def grouper(n, iterable, fillvalue=None):
    "grouper(3, 'ABCDEFG', 'x') --> ABC DEF Gxx"
    args = [iter(iterable)] * n
    return izip_longest(fillvalue=fillvalue, *args)

（使用 [iter（iterable）] * n 多次压缩相同的迭代器是一个老技巧，但将其封装在此函数中避免了混淆代码，并且它是完全相同的形式很多人都会使用这个界面。这是一个有点普遍的需求，实际上并不是在 itertools 模块。）

(Zipping the same iterator several times with [iter(iterable)]*n is an old trick, but encapsulating it in this function avoids confusing code, and it is the same exact form and interface many people will use. It's a somewhat common need and it's a bit of a shame it isn't actually in the itertools module.)

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