Read a file line-by-line instead of read file into memory

Question

I´m having some trouble with reading a file line-by-line, instead of reading the the file into memory. As of right now, I\'m reading the file into memory, and it works perfect.

Answer 1

To return to the beginning of the file, use seek:

def read(filename):

    with open(filename, 'r') as f: #open the file

        A = sum(float(line) for line in f)
        f.seek(0)
        B = sum(float(line)**2 for line in f)

            print(B)