Putting integers into a list from a text file

Question

I have a text file and I need to put the numbers in this file into a list like this: [[123,456],[234,567],[345,678]...] but I don't know how to do this as I ran into some error messages shown below.

My text file looks something like this (the --> are arrows in the original text file, but I don't know what they look like if I read the file using with open :

# These are the ids for blablabla
# put the ids into a list like this [[123,456],[234,567],[345,678]...]
#id1 --> id2
#123 --> 456
#234 --> 567
#345 --> 678
#456 --> 789

What I tried to do initially was

with open('mytxt.txt', 'r') as f:
    for line in range(3):
        next(f)
    for line in f:
        lst = list(map(int,line.split(',')))
        print(lst)[:10]

After running this, I got an error message <:-- language: lang-js --> invalid literal for int() with base 10: '123\t456\n' so I thought about stripping the '\n' and the 't' at the end of each line by running the following code:

with open('ca-GrQc.txt', 'r') as f:
    for line in range(4):
        next(f)
    for line in f:
        lst = list(map(int,line.strip('\n').strip('t').split(',')))
        print(lst)[:10]

After running that I still got an error message invalid literal for int() with base 10: '123\t456' which I have no idea where the 't' comes from (and I am sure that 't' was not in the orginal file).

Does anyone know why that happens and how to solve it, or is there a more efficient way of putting the numbers from the text file into a list?

Answer 1

You can use regex to achieve your expected output.

import re
file1 = open("names_file.txt", "r")
l = file1.readlines()
new_list = []
for i in l:
    m = re.findall(r'\d+', i)
    new_list.append(m)
print(new_list)

Above code will give a list containing strings, if you want to convert it into integer type then add this code. This will give your expected output.

for j in range(len(new_list)):
    for k in range(2):
        new_list[j][k] = int(new_list[j][k])
print(new_list)

There are two print statement in above code one will give list of list of string, and after conversion it will give list of list of integers.