Python理解中是否需要局部变量? [英] Is local variable necessary in Python comprehensions?

问题描述

在Python 3.x中，我正在调用一个函数rand_foo()，该函数每次被调用时都会返回一些随机的东西.我希望将随机结果序列存储到列表中.我正在使用以下构造:

r = [ rand_foo() for i in range(10) ]

现在我的PyCharm 3.0 IDE会继续发出警告:Local variable 'i' value is not used.

是否有一种优雅的方法来删除不必要的变量?确实，在某些情况下，我可以使用itertools.repeat()或类似10*[value]的东西，但是，不能将其应用于上面的示例.

解决方案

未使用变量时的约定是使用下划线:

r = [rand_foo() for _ in range(10)]

例如，请参见:下划线_作为Python中的变量名

我相信这会抑制您的PyCharm警告

In Python 3.x, I'm calling a function rand_foo() which returns some random stuff each time being called. I wish to store the sequence of random results into a list. I'm using the following construct:

r = [ rand_foo() for i in range(10) ]

Now my PyCharm 3.0 IDE keeps warning: Local variable 'i' value is not used.

Is there an elegant way of removing the unnecessary variable? Indeed, in some cases, I could use itertools.repeat() or something like 10*[value], which, however, cannot be applied to my example above.

解决方案

The convention when a variable is unused is to use an underscore instead:

r = [rand_foo() for _ in range(10)]

See for example: Underscore _ as variable name in Python

I believe this will suppress your PyCharm warning

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