File: lentimer.py

"test the relative speeds of len(X) versus X.__len__()"
import time, sys
def timer(func, reps=50):
 """
 time the best of N runs of a zero-arg function;
 see also generalized timer() in the book LP4E,
 pages 509..518, in Chapter 20, Functions part
 """
 best = 2 ** 32
 for i in range(reps):
 start = time.clock()
 retval = func()
 elapsed = time.clock() - start
 if elapsed < best:
 best = elapsed
 return (best, retval)
# hoist out and equate range() time: list in 2.X, generator in 3.X
innerloop = list(range(500000))
#
# test cases: both take len of 500k list, 500k times
#
def builtinFunc():
 for i in innerloop:
 x = len(innerloop)
 return x
def underMethod():
 for i in innerloop:
 x = innerloop.__len__()
 return x
if __name__ == '__main__':
 print(sys.version.split()[0])
 for func in (builtinFunc, underMethod):
 print(func.__name__)
 print(timer(func))