# join_vs_concat_surprise.py

# join_vs_concat_surprise.py

from time import clock

def timer(test):
    ttt = clock()
    exec(test)
    print test
    print "{:.8f}".format(clock()-ttt)
    print

limit = 10**6

def concat_str():
    resp = ''
    for num in xrange(limit):
        resp += `num`
    return resp

timer('''concat_str()''')

def join_list():
    return ''.join([`num` for num in xrange(limit)])

timer('''join_list()''')