Python – Create nested lists from file columns (Python)

I’m trying to create a nested list with lines from a .txt file, but it doesn’t get to the form I want.

.txt file contents:

[1,2,3]  
[2,3,4]  
[3,4,5]

Code:

nested_List = []
file = open("example_File.txt",'r')
    for i in file:
        element = i.rstrip("\n")
        nested_List.append(element)
arch.close()
return (esta)

The result I got:

['[1,2,3]', '[2,3,4]', '[3,4,5]']

What I want:

[[1,2,3],[2,3,4],[3,4,5]]

You need to convert the string representing the list to the actual list. You can use ast.literal_eval like:

from ast import literal_eval

nested_list = []
with open("file1", 'r') as f:
    for i in f:
        nested_list.append(literal_eval(i))
print(nested_list)

Or use list comprehension like:

with open("file1", 'r') as f:
    nested_list = [literal_eval(line) for line in f]
print(nested_list)

Result:

[[1, 2, 3], [2, 3, 4], [3, 4, 5]]