how to read and add stirng and write back each line in python ?

Question

I need to open a file to read each line, then add a string at the end of each line. And then, write back the new line the opened file.

    number = 0 
    with open("test_openFile.txt", "r+b") as the_file:
    for line in the_file:
        print (line)
        type(line)
        line = line.strip('\n') + "\t" + str(number)
        number += 1
        the_file.write(line)

But, I got:

  line = line.strip('\n')
  TypeError: Type str doesn't support the buffer API

Any help would be appreciated !

Answer 1

Try it like this

import fileinput

for line in fileinput.input("myfile.txt", inplace=1):
    print line.strip() + " a cool string"

that will add " a cool string" to the end of every line

Answer 2

Try this:

import os
fd_r=open('whatever.txt','r').readlines()
fd_w=open('whatever.txt','w')

for line in fd_r:
    line=line.strip()+" adding 1234"
    fd_w.write(line+"\n")
fd_w.close()  

This will append the string " adding 1234" to every line.