Convert a complex string to a list in python

Question

I retrieved the sting below form mysql table using python and I am having difficulty converting it into a list.

_string='[1,2,3,4]'

My attempt

>>> _string='[1,2,3,4]'
>>> sum(list(_string),[])
>>> list(_string)
['[', '1', ',', '2', ',', '3', ',', '4', ']']

>>> _string.strip('\n')
'[1,2,3,4]'

Desired output:

[1,2,3,4]

Is there and efficient way to get the desired output? as I will be doing a millions.

Mazdak · Answer 1 · 2015-05-23T11:39:59.037

3

Its what that ast.literal_eval is for,you can simply use it to safely evaluating strings containing Python values :

>>> _string='[1,2,3,4]'
>>> 
>>> import ast
>>> ast.literal_eval(_string)
[1, 2, 3, 4]

edited May 23 '15 at 11:39

answered May 23 '15 at 11:34

Mazdak

105,000
18
159
188

score 1 · Accepted Answer · answered May 23 '15 at 11:40

1

Generalizing a bit - if your string is always a JSON formatted list, you could go with:

data = json.loads('[1, 2, 3, 4]')

answered May 23 '15 at 11:40

OrenD

1,751
13
12

your solution is just what I wanted. Thanks you. – user2274879 May 23 '15 at 11:48

score 0 · Answer 3 · answered May 23 '15 at 11:34

0

Try this:

your_list = _string.strip("[]").split(",")

answered May 23 '15 at 11:34

shaktimaan

1,769
13
14

score 0 · Answer 4 · answered May 23 '15 at 11:42

0

Using List comprehension and split

In [14]: [int(i) for i in _string[1:-1].split(',')]
Out[14]: [1, 2, 3, 4]

answered May 23 '15 at 11:42

Ajay

5,267
2
23
30

Convert a complex string to a list in python

4 Answers4