Python reading file into two lists of integers

Question

I wanted to read a file and extract two lists of doubles for example, file.txt contains the following:

123 345 456 8919
231 521 363 1716

separated by a white space ' '. I have the following code to read the above file:

    with open("file.txt") as f:
        for line in f.readline():
            cipher_array.append(line.split()[0])
            cipher_array.append(line.split()[1])
            halfmask.append(line.split()[2]) 
            halfmask.append(line.split()[3]) 

I get the following error:

 cipher_array.append(line.split()[1])
IndexError: list index out of range

I want to have cipher_array to consist of [123, 345, 231, 521] and halfmask = [456, 8919, 363, 1716]

What is wrong with my code? Thanks in advance

Answer 1

use split(" ") instead of split() also f.readline() should be f.readlines()

cipher_array,halfmask=[],[]
with open("file.txt") as f:
    for line in f.readlines():
        cipher_array.append(float(line.split(" ")[0]))
        cipher_array.append(float(line.split(" ")[1]))
        halfmask.append(float(line.split(" ")[2]) )
        halfmask.append(float(line.split(" ")[3]))
cipher_array,halfmask