import time
from itertools import imap
lst = range(100000)
times = []
for i in xrange(10):
    t = time.time()
    s = ""
    for k in lst:
        s += str(k)
    times.append(time.time()-t)
print "for time avrg:", sum(times) * 1.0 / 10.0

times = []
for i in xrange(10):
    t = time.time()
    s = "".join(imap(str,lst))
    times.append(time.time()-t)
print "join time avrg:", sum(times) * 1.0 / 10.0