Question

I would like to create a function that keeps a record of every print command, storing each command’s string into a new line in a file.

def log(line):
    with open('file.txt', "a") as f:
        f.write('\n' + line)

This is what I have, but is there any way to do what I said using Python?

Answer 1

Try replacing stdout with custom class:

import sys
class LoggedStdout():
    def __init__(self, filename = None):
        self.filename = filename
    def write(self, text):
        sys.__stdout__.write(text)
        if not self.filename is None:
            self.log(text)
    def log(self, line):
        with open(self.filename, "a") as f:
            f.write('\n' + line)

sys.stdout = LoggedStdout('file.txt')

print 'Hello world!'

This would affect not only print, but also any other function that prints something to stdout, but it is often even better.

For production-mode logging it’s much better to use something like logging module, rather than home-made hooks over standard IO streams.