str number benchmarks

number_string.py

>>> import timeit
>>> timeit.Timer('str(n)','n=100000').timeit()
0.31551924882785443
>>> timeit.Timer('"%s"%n','n=100000').timeit()
0.27519383648404983
>>> timeit.Timer('"{0}".format(n)','n=100000').timeit()
0.5812355446599895

The previous benchmark was wrong.
Check stackoverflow thread http://stackoverflow.com/questions/10530315/str-performance-in-python