“int(a[::-1])"是什么意思?在 Python 中? [英] What is the meaning of "int(a[::-1])" in Python?

问题描述

我无法理解这一点.我在人们的代码中看到了这一点.但无法弄清楚它的作用.这是在 Python 中.

str(int(a[::-1]))

解决方案

假设 a 是一个字符串.python 中的 Slice 符号具有语法 -

list[::]

因此，当您执行 a[::-1] 时，它会从末尾开始向第一个获取每个元素.所以它反转了a.这也适用于列表/元组.

示例 -

<预><代码>>>>一个 = '1234'>>>[::-1]'4321'

然后你把它转换成 int 然后再转换回字符串(虽然不知道你为什么这样做)，这只会给你返回字符串.

I cannot understand this. I have seen this in people's code. But cannot figure out what it does. This is in Python.

str(int(a[::-1]))

解决方案

Assuming a is a string. The Slice notation in python has the syntax -

list[<start>:<stop>:<step>]

So, when you do a[::-1], it starts from the end towards the first taking each element. So it reverses a. This is applicable for lists/tuples as well.

Example -

>>> a = '1234'
>>> a[::-1]
'4321'

Then you convert it to int and then back to string (Though not sure why you do that) , that just gives you back the string.

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