Reddit Daily Programmer Challenge: Run Length Encoding

challenge.py

#!/usr/bin/python

# Challenge: http://www.reddit.com/r/dailyprogrammer/comments/xxbbo/882012_challenge_86_easy_runlength_encoding/
# Solution: http://www.reddit.com/r/dailyprogrammer/comments/xxbbo/882012_challenge_86_easy_runlength_encoding/c5qf7af
# Run code online: http://ideone.com/DwxRr

import sys
import re

if len(sys.argv) == 1:
    print 'Enter a string as input'
    exit()

input = sys.argv[1]

items = []
idx = 0

while idx < len(input):
	char = input[idx]
	pattern = re.compile(r"[^" + char + "]")
	match = pattern.search(input, idx)
	if match:
		items.append( (match.start() - idx, char) )
		idx = match.start()
	else:
		items.append( (len(input) - idx, char) )
		break

print items

bonus = ''
for item in items:
	bonus += item[0] * item[1]

print bonus