Hackerrank - capitalize

#!/bin/python3

import re

# Complete the solve function below.

# METHOD 1 - Regular expressions
word_start = re.compile(r'(?<=\b)\w')
capitalize = lambda m: m.group().upper()

def solveRE(s):
    return word_start.sub(capitalize, s)

# METHOD 2 - zip / comprehension
def solveZip(s):
    return ''.join(y.upper() if x == ' ' else y for x,y in zip(' '+s, s))

# METHOD 3 - me is noob
def solveNoob(s):
    l = list(s)
    l[0] = l[0].upper()
    for i in range(1, len(l)):
        if l[i-1] == ' ':
            l[i] = l[i].upper()
    return ''.join(l)

# change the method to one of "solveRE", "solveZip", "solveNoob"
solve = solveRE