How to read a list in a text file in python

Question

I have this list

l1=[[[0,1,2,3,4],[5,6,7]],[8,9,10],[11,12,13,14]]

and I save this list in a text file

with open('l1.txt', 'w') as f1:
      f1.write(str(l1))

Now I have a text file with the list. How can I read this list in python? I tried with

list1= open("l1.txt", "r")
list2= list1.read()
l1= list2.strip('][').split(', ')

With this I have

l1=['0','1','2','3','4','5','6','7','8','9','10','11','12','13','14']

but this isn't the list I have at the beginning

Answer 1

As @Cardstdani mentioned, you can try to use eval. However, I suggest avoiding eval in all but the rarest of cases.

I would suggest serialising and deserialising it in some nice, way, such as using JSON:

Save:

import json

l1=[[[0,1,2,3,4],[5,6,7]],[8,9,10],[11,12,13,14]]

with open("l1.json", "w") as f:
    json.dump(l1, f)

Load:

import json

with open("l1.json") as f:
    l1 = json.load(f)