How to search and replace text in a file?

Question

How do I search and replace text in a file using Python 3?

Here is my code:

import os
import sys
import fileinput

print (\"Text to search for:\")
te         


        

Answer 1

As Jack Aidley had posted and J.F. Sebastian pointed out, this code will not work:

 # Read in the file
filedata = None
with file = open('file.txt', 'r') :
  filedata = file.read()

# Replace the target string
filedata.replace('ram', 'abcd')

# Write the file out again
with file = open('file.txt', 'w') :
  file.write(filedata)`

But this code WILL work (I've tested it):

f = open(filein,'r')
filedata = f.read()
f.close()

newdata = filedata.replace("old data","new data")

f = open(fileout,'w')
f.write(newdata)
f.close()

Using this method, filein and fileout can be the same file, because Python 3.3 will overwrite the file upon opening for write.