从Python中的列表中删除奇数索引元素 [英] Remove odd-indexed elements from list in Python

问题描述

我正在尝试从列表中删除奇数索引的元素(其中零被视为偶数)，但是以这种方式删除它们将不起作用，因为它会抛弃索引值.

I'm trying to remove the odd-indexed elements from my list (where zero is considered even) but removing them this way won't work because it throws off the index values.

lst = ['712490959', '2', '623726061', '2', '552157404', '2', '1285252944', '2', '1130181076', '2', '552157404', '3', '545600725', '0']


def remove_odd_elements(lst):
    i=0
    for element in lst:
        if i % 2 == 0:
            pass
        else:
            lst.remove(element)
        i = i + 1

如何遍历列表并干净地删除那些索引奇数的元素?

How can I iterate over my list and cleanly remove those odd-indexed elements?

推荐答案

您可以使用演示:

>>> lst = ['712490959', '2', '623726061', '2', '552157404', '2', '1285252944', '2', '1130181076', '2', '552157404', '3', '545600725', '0']
>>> del lst[1::2]
>>> lst
['712490959', '623726061', '552157404', '1285252944', '1130181076', '552157404', '545600725']

在迭代列表时，不能从列表中删除元素，因为列表迭代器在删除项目时不会进行调整.参见循环"Forgets"删除一些项目尝试时会发生什么情况.

You cannot delete elements from a list while you iterate over it, because the list iterator doesn't adjust as you delete items. See Loop "Forgets" to Remove Some Items what happens when you try.

一种替代方法是使用 enumerate() 提供索引:

An alternative would be to build a new list object to replace the old, using a list comprehension with enumerate() providing the indices:

lst = [v for i, v in enumerate(lst) if i % 2 == 0]

此保留偶数元素，而不是删除奇数元素.

This keeps the even elements, rather than remove the odd elements.

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