sed.py

"""This module contains a code example related to

Think Python, 2nd Edition

by Allen Downey

http://thinkpython2.com

Copyright 2015 Allen Downey

License: http://creativecommons.org/licenses/by/4.0/

"""

from __future__ import print_function, division

def sed(pattern, replace, source, dest):

"""Reads a source file and writes the destination file.

In each line, replaces pattern with replace.

pattern: string

replace: string

source: string filename

dest: string filename

"""

fin = open(source, 'r')

fout = open(dest, 'w')

for line in fin:

line = line.replace(pattern, replace)

fout.write(line)

fin.close()

fout.close()

def main():

pattern = 'pattern'

replace = 'replace'

source = 'sed_tester.txt'

dest = source + '.replaced'

sed(pattern, replace, source, dest)

if __name__ == '__main__':

main()