python 定时执行指定的函数详解编程语言

python 定时执行指定的函数

# time a function using time.time() and the a @ function decorator 
# tested with Python24    vegaseat    21aug2005 
  
import time 
  
def print_timing(func): 
    def wrapper(*arg): 
        t1 = time.time() 
        res = func(*arg) 
        t2 = time.time() 
        print '%s took %0.3f ms' % (func.func_name, (t2-t1)*1000.0) 
        return res 
    return wrapper 
  
# declare the @ decorator just before the function, invokes print_timing() 
@print_timing 
def getPrimeList(n): 
    """ returns a list of prime numbers from 2 to < n using a sieve algorithm""" 
    if n < 2:  return [] 
    if n == 2: return [2] 
    # do only odd numbers starting at 3 
    s = range(3, n+1, 2) 
    # n**0.5 may be slightly faster than math.sqrt(n) 
    mroot = n ** 0.5 
    half = len(s) 
    i = 0 
    m = 3 
    while m <= mroot: 
        if s[i]: 
            j = (m*m-3)//2 
            s[j] = 0 
            while j < half: 
                s[j] = 0 
                j += m 
        i = i+1 
        m = 2*i+3 
    return [2]+[x for x in s if x] 
  
if __name__ == "__main__": 
    print "prime numbers from 2 to <10,000,000 using a sieve algorithm" 
    primeList = getPrimeList(10000000) 
    time.sleep(2.5) 
      
""" 
my output --> 
prime numbers from 2 to <10,000,000 using a sieve algorithm 
getPrimeList took 4750.000 ms 
"""