Replace a whole line in a txt file

Question

I'am new to Python 3 and could really use a little help. I have a txt file containing:

InstallPrompt=

DisplayLicense=

FinishMessage=

TargetName=D:\somewhere

FriendlyName=something

I have a python script that in the end, should change just two lines to:

TargetName=D:\new

FriendlyName=Big

Could anyone help me, please? I have tried to search for it, but I didnt find something I could use. The text that should be replaced could have different length.

Answer 1

import fileinput
for line in fileinput.FileInput("file",inplace=1):
    sline=line.strip().split("=")
    if sline[0].startswith("TargetName"):
        sline[1]="new.txt"
    elif sline[0].startswith("FriendlyName"):
        sline[1]="big"
    line='='.join(sline)    
    print(line)

Answer 2

A very simple solution for what you're doing:

#!/usr/bin/python
import re
import sys
for line in open(sys.argv[1],'r').readlines():
  line = re.sub(r'TargetName=.+',r'TargetName=D:\\new', line)
  line = re.sub(r'FriendlyName=.+',r'FriendlyName=big', line)
  print line,

You would invoke this from the command line as ./test.py myfile.txt > output.txt