for i in range(100): print i; s = ""; for i in range(100): s += str(i); print s; // concatenating the first 100 numbers into a string s = ""; for i in range(100): s += str(i); print s; import timeit def redefine(): s = "" for i in range(100): s += str(i); timeit.timeit("redefine()", setup="from __main__ import redefine; gc.enable()", number=1) timeit.repeat("redefine()", setup="from __main__ import redefine") timeit.timeit('redefine()', number=10000) import timeit def combine(): s = "".join(str(range(100))) timeit.timeit("combine()", setup="from __main__ import combine; gc.enable()", number=1)