Python中的数组索引 [英] Array Indexing in Python

问题描述

在这里开始学习python的人在想什么.

Beginner here, learning python, was wondering something.

这给了我第二个要素:

list = [1,2,3,4]
list.index(2)
2

但是当我尝试这样做时:

But when i tried this:

list = [0] * 5
list[2] = [1,2,3,4]
list.index[4]

我得到一个错误.有什么方法可以从数组中拉出元素的索引，而不管它放在什么列表中?我知道字典是可能的:

I get an error. Is there some way to pull the index of an element from an array, no matter what list it's placed into? I know it's possible with dictionaries:

info = {first:1,second:2,third:3}
for i in info.values:
print i
1
2
3

列表有类似的东西吗?

推荐答案

index 方法无法达到您的期望.要获得索引项，必须使用 [] 语法:

The index method does not do what you expect. To get an item at an index, you must use the [] syntax:

>>> my_list = ['foo', 'bar', 'baz']
>>> my_list[1]  # indices are zero-based
'bar'

index 用于从项目中获取索引:

index is used to get an index from an item:

>>> my_list.index('baz')
2

如果您要问是否有任何方法可以使 index 递归到子列表中，答案是否定的，因为它必须返回某些内容，然后您可以将其传递给[] 和 [] 从不进入子列表.

If you're asking whether there's any way to get index to recurse into sub-lists, the answer is no, because it would have to return something that you could then pass into [], and [] never goes into sub-lists.

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