获取发电机的子集 [英] Get a subset of a generator

问题描述

我有一个生成器函数，想从中获取前十项；我的第一次尝试是:

I have a generator function and want to get the first ten items from it; my first attempt was:

my_generator()[:10]

这是行不通的，因为错误无法告诉生成器，因此生成器不可下标.现在，我已经通过以下方法解决了这个问题:

This doesn't work because generators aren't subscriptable, as the error tells me. Right now I have worked around that with:

list(my_generator())[:10]

这有效，因为它将生成器转换为列表；但是，它效率低下，无法使用发电机.生成器是否有与[:10]相同的内置Pythonic版本?

This works since it converts the generator to a list; however, it's inefficient and defeats the point of having a generator. Is there some built-in, Pythonic equivalent of [:10] for generators?

推荐答案

import itertools

itertools.islice(mygenerator(), 10)

itertools具有许多用于迭代器的实用程序. islice使用开始，停止和步进参数来切片迭代器，就像切片列表一样.

itertools has a number of utilities for working with iterators. islice takes start, stop, and step arguments to slice an iterator just as you would slice a list.

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