# 为什么一个可以翻转，一个是none

**URL:** <https://forum.freecodecamp.org/t/none/577963>\
**Category:** General\
**Tags:** chinese-中文\
**Created:** [December 14, 2022, 1:24pm UTC](https://forum.freecodecamp.org/t/none/577963 "2022-12-14T13:24:21Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![LKDDM](https://avatars.discourse-cdn.com/v4/letter/l/ec9cab/32.png) [@LKDDM](https://forum.freecodecamp.org/u/LKDDM)\
**Post date:** [December 14, 2022, 1:24pm UTC](https://forum.freecodecamp.org/t/none/577963/1 "2022-12-14T13:24:21Z")

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Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) [MSC v.1916 64 bit (AMD64)] on win32  
Type “help”, “copyright”, “credits” or “license()” for more information.

> > > L1=[4,5,6,8]  
> > > L1.reverse()  
> > > print(L1)  
> > > [8, 6, 5, 4]  
> > > L1=[4,5,6,8].reverse()  
> > > print(L1)  
> > > None  
> > > L1=[4,5,6,8]  
> > > L1=[4,5,6,8].reverse()  
> > > print(L2)  
> > > Traceback (most recent call last):  
> > > File “\<pyshell#7\>”, line 1, in   
> > > print(L2)  
> > > NameError: name ‘L2’ is not defined  
> > > L1=[4,5,6,8]  
> > > L2=[4,5,6,8].reverse()  
> > > print(L2)  
> > > None

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**Author:** ![luojiyin1987](https://sea3.discourse-cdn.com/freecodecamp/user_avatar/forum.freecodecamp.org/luojiyin1987/32/241573_2.png) [@luojiyin1987](https://forum.freecodecamp.org/u/luojiyin1987)\
**Post date:** [December 14, 2022, 1:44pm UTC](https://forum.freecodecamp.org/t/none/577963/2 "2022-12-14T13:44:29Z")

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list.reverse() 无返回值 所以得到 None 。 只会改变 list 的值，所以第一个L1 的值变了

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**Author:** ![ILM](https://sea3.discourse-cdn.com/freecodecamp/user_avatar/forum.freecodecamp.org/ilm/32/363239_2.png) [@ILM](https://forum.freecodecamp.org/u/ILM)\
**Post date:** [January 7, 2025, 3:40pm UTC](https://forum.freecodecamp.org/t/none/577963/3 "2025-01-07T15:40:51Z")

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Closed on January 7, 2025, 3:40pm UTC