Python中的动态变量 [英] Dynamic variable in Python

问题描述

例如，如何在python中创建具有动态名称的列表

How can I create lists with dynamic names in python, for example

for i in range(len(myself)):
   list(i) = []

我应该用什么代替list(i)? 这意味着我想要一些名字，如下所示:

what should I use instead of list(i) ? it means that i want some names as below:

list1
list2
list3
...

推荐答案

我建议您只使用列表或字典，而不要使用动态变量名.下面的所有版本都会导致lists[0]，lists[1]等为[]，这似乎与您想要的内容足够接近，并且从长远来看将更具可读性/可维护性. (注意:我使用lists而不是list作为变量名，因为后者会覆盖内置的list函数，您可能不希望这样做).

I'd advise you to just use a list or dictionary instead of dynamic variable names. All the versions below result in lists[0], lists[1] etc being [], which seems close enough to what you want, and will be more readable/maintainable in the long term. (Note: I'm using lists instead of list as a variable name because the latter would overwrite the builtin list function, which you probably don't want).

1)版本，其中lists是列表列表(数字只是列表的顺序):

1) Version with lists being a list of lists (the numbers are just the order of the lists):

lists = [[] for i in range(len(myself))]

2)相同，但是具有for循环而不是列表理解:

2) Same but with a for loop instead of a list comprehension:

lists = []
for i in range(len(myself)):
   lists.append([])

3)版本为lists是包含数字作为键的列表的字典(如果您以后要删除某些值，则更加灵活):

3) Version with lists being a dictionary of lists with numbers as keys (a bit more flexible if you want to remove some of the values later or such):

lists = {}
for i in range(len(myself)):
   lists[i] = []

关于动态变量名，即像list1而不是lists[1]这样的变量...说真的，您可能不应该这样做.它不必要地复杂且难以维护.考虑一下-下个月，您将要修改脚本，然后尝试找出变量list1的定义位置，而纯文本搜索将无法做到这一点.这很痛苦.
但是，如果您确实出于某些原因想要这样做，可以通过exec-此处有一些原因不使用它-或修改locals()-不好根据文档的想法.另请参阅评论，以获取更多讨论，讨论为什么这些东西不是一个好主意，甚至甚至在谈论这些问题时都令人困惑.

About dynamic variable names, i.e. variables like list1 instead of lists[1]... Seriously, you probably shouldn't do that. It's unnecessarily complicated and hard to maintain. Think about it - next month you'll want to modify the script, and you'll try to figure out where the variable list1 was defined, and you won't be able to do that with a plain text search. It's a pain.
But if you really want to for some reason, it's possible with exec - here are some reasons not to use it - or with modifying locals() - bad idea according to documentation. Also see comments for more discussion on why these things are a bad idea and how confusing it gets even talking about them.

这篇关于Python中的动态变量的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！