python实现简单的计时器功能函数

''' Simple Timing Function.This function prints out a message with the elapsed time from theprevious call. It works with most Python 2.x platforms. The functionuses a simple trick to store a persistent variable (clock) withoutusing a global variable.'''import timedef dur( op=None, clock=[time.time()] ):  if op != None:    duration = time.time() - clock[0]    print '%s finished. Duration %.6f seconds.' % (op, duration)  clock[0] = time.time()# Exampleif __name__ == '__main__':  import array  dur()  # Initialise the timing clock  opt1 = array.array('H')  for i in range(1000):    for n in range(1000):      opt1.append(n)  dur('Array from append')  opt2 = array.array('H')  seq = range(1000)  for i in range(1000):    opt2.extend(seq)  dur('Array from list extend')  opt3 = array.array('H')  seq = array.array('H', range(1000))  for i in range(1000):    opt3.extend(seq)  dur('Array from array extend')# Output:# Array from append finished. Duration 0.175320 seconds.# Array from list extend finished. Duration 0.068974 seconds.# Array from array extend finished. Duration 0.001394 seconds.