列表的逻辑索引 [英] Logical indexing with lists

问题描述

本节中有我正在浏览的程序

I have a program I'm looking through and with this section

temp = [1,2,3,4,5,6]
temp[temp!=1]=0
print temp

如果运行将给出结果:

[1, 0, 3, 4, 5, 6]

我需要帮助来理解这段代码中导致结果的事情.

I need help understanding what is going on in this code that leads to this result.

推荐答案

正如已经说明的，您正在使用与返回True/1作为 bool是int的子类.您有一个列表而不是一个numpy数组，因此如果要更改它，则需要对其进行迭代，这可以使用 if/els e逻辑使用列表理解来完成:

As Already explained you are setting the second element using the result of comparing to a list which returns True/1 as bool is a subclass of int. You have a list not a numpy array so you need to iterate over it if you want to change it which you can do with a list comprehension using if/else logic:

temp = [1,2,3,4,5,6]
temp[:] = [0 if ele != 1 else ele for ele in temp ]

哪个会给你:

[1, 0, 0, 0, 0, 0]

或使用生成器表达式:

temp[:] = (0 if ele != 1 else ele for ele in temp)

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