具有负步幅的 Python range() [英] Python range() with negative strides

问题描述

有没有办法在步幅为 -1 的情况下使用 range() 函数?

Is there a way of using the range() function with stride -1?

例如使用 range(10, -10) 而不是下面的方括号值?

E.g. using range(10, -10) instead of the square-bracketed values below?

即以下行:

for y in range(10,-10)

代替

for y in [10,9,8,7,6,5,4,3,2,1,0,-1,-2,-3,-4,-5,-6,-7,-8,-9,-10]:

显然，可以用另一种更优雅的循环来做到这一点，但 range() 示例对我想要的效果会更好.

Obviously one could do this with another kind of loop more elegantly but the range() example would work much better for what I want.

推荐答案

您可以指定步幅(包括负步幅)作为第三个参数，所以

You can specify the stride (including a negative stride) as the third argument, so

range(10,-11,-1)

给予

[10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -10] 

一般来说，尝试不需要任何费用.您可以简单地将其输入到解释器中，然后查看它的作用.

In general, it doesn't cost anything to try. You can simply type this into the interpreter and see what it does.

这都是记录在这里:

range(start, stop[, step])

但主要是我想鼓励你玩玩，看看会发生什么.如您所见，您的直觉很准.

but mostly I'd like to encourage you to play around and see what happens. As you can see, your intuition was spot on.

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