How to extract a list of lists from a .txt file in python

Question

I want to extract a list of lists from a .txt file. The data in the .txt file is given like this:

[[[12,34.2,54.1,46.3,12.2],[9.2,63,23.7,42.6,15.2]],
  [[12,34.2,54.1,46.3,12.2],[9.2,63,23.7,42.6,15.2]],
  [[12,34.2,54.1,46.3,12.2],[9.2,63,23.7,42.6,15.2]]]

I want to store it in a list like:

listA = [[[12,34.2,54.1,46.3,12.2], [9.2,63,23.7,42.6,15.2]], [[12,34.2,54.1,46.3,12.2], [9.2,63,23.7,42.6,15.2]],[[12,34.2,54.1,46.3,12.2], [9.2,63,23.7,42.6,15.2]]]

I tried using the read() function, but it reads as a string, and I can't seem to find out how to extract what I want.

This doesn't look like a TXT file, it looks like a JSON file. — Thomas Weller, Nov 15 '22 at 11:43
Assuming this is json use the [json](https://docs.python.org/2.7/library/json.html) module. — Iguananaut, Nov 15 '22 at 11:45
This file is given to me in the exact same format in a .txt file — Dimitrios Priovolos, Nov 15 '22 at 12:04

score 0 · Answer 1 · answered Nov 15 '22 at 11:47

0

This is how you import a file https://docs.python.org/3/library/fileinput.html

and this is how you parse it https://www.w3schools.com/python/python_json.asp

answered Nov 15 '22 at 11:47

Jatel

40
8

score 0 · Answer 2 · answered Nov 15 '22 at 12:26

You can use literal_eval method from ast package to parse string representation of list:

str_list = '''[
  [
    [12,34.2,54.1,46.3,12.2],
    [9.2,63,23.7,42.6,15.2]
  ],
  [
    [12,34.2,54.1,46.3,12.2],
    [9.2,63,23.7,42.6,15.2]
  ],
  [
    [12,34.2,54.1,46.3,12.2],
    [9.2,63,23.7,42.6,15.2]
  ]
]'''

import ast
parsed_list = ast.literal_eval(str_list)
print(parsed_list)

Output:

[[[12, 34.2, 54.1, 46.3, 12.2], [9.2, 63, 23.7, 42.6, 15.2]], [[12, 34.2, 54.1, 46.3, 12.2], [9.2, 63, 23.7, 42.6, 15.2]], [[12, 34.2, 54.1, 46.3, 12.2], [9.2, 63, 23.7, 42.6, 15.2]]]

How to extract a list of lists from a .txt file in python

2 Answers2