Adding a string variable to the beginning of each string in a readlines structure

Question

I have imported a file and used readlines to split each line into a string. I have another variable, "SubID", that I want to add to the beginning of each line. Here is the code I have tried.

lines = file.readlines()
[SubID] + lines

Answer 1

You need to add your prefix to each line. Here's one method:

#!/usr/bin/env python2.7

import os

file_name = "test.txt"
file_handle = open(file_name, "r")

line_prefix = "[SubID]"

for line in file_handle.readlines():
    print line_prefix + ":", line.rstrip(os.linesep)