Python - How to add a space string (' ') to the end of every line in a text/conf file

Question

I have a config file that i would like to add a space (\' \') to the end of every line in the file

File example:

#xxx configuration
IPad         


        

Answer 1

You don't need to know the length of your file. In python files are iterators that yield lines. No need for c-style for-loops.

So something like this should work for you (python3 or from __future__ import print_function):

with open('file.in') as infile, open('file.out', 'w') as outfile:
    for line in infile:
        print(line.strip() + ' ', file=outfile)

Answer 2

You can use fileinput with inplace=True to update the original file:

import fileinput
import sys
for line in fileinput.input("in.txt",inplace=True):
    sys.stdout.write("{} \n".format(line.rstrip()))

Or use a tempfile.NamedTemporaryFile with shutil.move:

from tempfile import NamedTemporaryFile
from shutil import move

with open("in.txt") as f, NamedTemporaryFile("w",dir=".", delete=False) as temp:   
    for line in f:
       temp.write("{} \n".format(line.rstrip()))
move(temp.name,"in.txt")