CodeEval - String mask - Easy

import sys

 test_cases = open(sys.argv[1], 'r')
for test in test_cases:
    arr=test.split()
    string=""
    for i in range(len(arr[0])):
        if(int(arr[1][i])==0):
            string+=str(arr[0][i])
        else:
            string+=str(arr[0][i]).swapcase()
    print string
test_cases.close()