如何仅对元组的第一个变量进行迭代 [英] How can I iterate over only the first variable of a tuple

问题描述

在python中，当您有一个元组列表时，可以遍历它们.例如，当您有3d点时:

In python, when you have a list of tuples, you can iterate over them. For example when you have 3d points then:

for x,y,z in points:
    pass
    # do something with x y or z

如果只想使用第一个变量，或者第一个和第三个变量，该怎么办. python中是否有任何跳过符号?

What if you only want to use the first variable, or the first and the third. Is there any skipping symbol in python?

推荐答案

是否可以防止您不接触您不感兴趣的变量?在Python中，通常使用下划线来表示您不感兴趣的变量.例如:

Is something preventing you from not touching variables that you're not interested in? There is a conventional use of underscore in Python to indicate variable that you're not interested. E.g.:

for x, _,_ in points:
    print(x)

您需要了解这只是一个约定，与性能无关.

You need to understand that this is just a convention and has no bearing on performance.

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