Convert strings of list to list of integers inside a list

Question

I have a list of strings and those strings are lists. Like this: [\'[1,2,3]\',\'[10,12,5]\'], for example. I want to get a list of lists or even every list there: <

Answer 1

You can use ast.literal_eval, eval should generally be avoided:

l= ['[1,2,3]','[10,12,5]']

from ast import literal_eval

print([literal_eval(ele) for ele in l])
[[1, 2, 3], [10, 12, 5]]

Or index, split and map:

print([list(map(int,ele[1:-1].split(","))) for ele in l])
[[1, 2, 3], [10, 12, 5]]

If you always have the same format splitting is the most efficient solution:

In [44]: %%timeit                       
l= ['[1,2,3]','[10,12,5]']
l = [choice(l) for _ in range(1000)]
[eval(ele) for ele in l]
   ....: 
100 loops, best of 3: 8.15 ms per loop

In [45]: %%timeit
l= ['[1,2,3]','[10,12,5]']
l = [choice(l) for _ in range(1000)]
[literal_eval(ele) for ele in l]
   ....: 
100 loops, best of 3: 11.4 ms per loop

In [46]: %%timeit                       
l= ['[1,2,3]','[10,12,5]']
l = [choice(l) for _ in range(1000)]
[list(map(int,ele[1:-1].split(","))) for ele in l]
   ....: 
100 loops, best of 3: 2.07 ms per loop