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 the
previous call. It works with most Python 2.x platforms. The function
uses a simple trick to store a persistent variable (clock) without
using a global variable.
'''
import time
def 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()
# Example
if __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.