I need to convert a string to a list in python 3, how would I do this?

Question

So I have a text file with a list saved in it, I know I could use some other object serialization for this, but I am just trying to do this with a text file cause why not. So I have a string variable, that has a list in it, but how do I turn the string back into a normal list. Here is my code

    #the normal list
    list1 = [1,2,3]

    #changing the list to a string so that it can be written to a text file
    str_list = str(list1)

So now what code do I need to change the list from a string to a normal list.

Łukasz Rogalski · Answer 1 · 2015-04-20T19:22:00.560

3

You may use ast module with literal_eval function:

import ast
l = ast.literal_eval(s)

Or json module (warning! it works only for some subset of string representations, e.g. list of numbers - example given by you):

import json
l = json.loads(s)

edited Apr 20 '15 at 19:22

answered Apr 20 '15 at 19:20

Łukasz Rogalski

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`s = "['Uh', 'oh']"` – vaultah Apr 20 '15 at 19:21
Yes, string representation isn't always valid json syntax. Although it's valid for OP testcase. I'm gonna clarify the answer. – Łukasz Rogalski Apr 20 '15 at 19:22

score 2 · Answer 2 · answered Apr 20 '15 at 19:21

2

You can use ast.literal_eval:

>>> s="[1,2,3]"
>>> from ast import literal_eval
>>> literal_eval(s)
[1, 2, 3]

answered Apr 20 '15 at 19:21

Mazdak

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I need to convert a string to a list in python 3, how would I do this?

2 Answers2