Pythonic way of converting a list embedded in a string to a list

Question

I am not sure if there is a solution for this on stack overflow; so apologies if this is a duplicate.

There are number of ways of converting the string:

s = '[1, 2, 3]'

to a list

t = [1, 2, 3]

but I am looking for the most straightforward pythonic way of doing this. Also, performance matters.

Yes I did. But given the performance, would eval be fine? I am simply dealing with integer lists here. — p0lAris, Dec 02 '13 at 07:36
I don't understand why some would down rank this. I couldn't find the answer. — p0lAris, Dec 02 '13 at 07:45

score 3 · Accepted Answer · edited Dec 02 '13 at 07:47

3

>>> import ast
>>> ast.literal_eval('[1,2,3]')
[1, 2, 3]

edited Dec 02 '13 at 07:47

thefourtheye

answered Dec 02 '13 at 07:41

alko

1

you mean `import ast` – vahid abdi Dec 02 '13 at 07:43
Yeah, I did just that. Thanks. – p0lAris Dec 02 '13 at 07:45
instead of importing ast , Just do eval('[1,2,3]') – Nilesh Dec 02 '13 at 07:59
1

@NileshG `eval` is unsafe and should not be used. `ast.literal_eval` is *much* safer – TerryA Dec 02 '13 at 08:09

score 1 · Answer 2 · answered Dec 02 '13 at 07:38

1

Why never use json library.

import json
# convert str to list 
t = json.loads(s)

# back to string
s2 = json.dumps(t)

answered Dec 02 '13 at 07:38

crazyzubr

For a list of integers, this is a reasonable approach. – alko Dec 02 '13 at 07:47

2 Answers2