convert string into 2 dimensional list with no imports

February 20, 2022

I need to convert a string representation into a 2 dimensional list.

I am trying to read inputs from a text file. All inputs follow a standard format where each line represents a different variable. When I read the following line from the input file using f.readline():

[[0, 2, 1, 2, 3, 0], [2, 0, 3, 0, 1, 0], [2, 0, 0, 3, 3, 0], [0, 2, 3, 0, 0, 3], [1, 2, 3, 1, 0, 2], [2, 1, 0, 1, 3, 0]]

This line is read in as a string, but I need it converted to a 2 dimensional list. A constraint for this project is I cannot use any packages, only base python.

How do I do this?

>Solution :

Something like that should work:

text = "[[0, 2, 1, 2, 3, 0], [2, 0, 3, 0, 1, 0], [2, 0, 0, 3, 3, 0], [0, 2, 3, 0, 0, 3], [1, 2, 3, 1, 0, 2], [2, 1, 0, 1, 3, 0]]"

output = []
for sublist in text.split('], '):
    sublist = sublist.replace('[',  '').replace(']', '')
    data = []
    for number in sublist.split(', '):
        data.append(int(number))
    output.append(data)
print(output)

Using list comprehension:

text = "[[0, 2, 1, 2, 3, 0], [2, 0, 3, 0, 1, 0], [2, 0, 0, 3, 3, 0], [0, 2, 3, 0, 0, 3], [1, 2, 3, 1, 0, 2], [2, 1, 0, 1, 3, 0]]"

output = [[int(number) for number in sublist.replace('[', '').replace(']', '').split(', ')] for sublist in text.split('], ')]
print(output)