Python 学习入门（38）—— @functools模块

killerxf

　　The functoolsmodule is for higher-order functions: functions that act on or return other functions. In general, any callable object can be treated as a function for the purposes of this module.

　　

　　functools 源码路径及内置函数：

　　

　　利用@functools对函数运行时间，进行计时
　　代码示例：

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# blog.ithomer.net
import time, functools
def timeit(func):
@functools.wraps(func)
def __do__(*args, **kwargs):
start = time.time()
result = func(*args, **kwargs)
print("%s usedtime: %ss" % (func.__name__, time.time() - start))
return result
return __do__
@timeit
def print_str(num):
sum = 0
for i in range(num):
sum += i
print sum
@timeit
def main():
print("print_str(100)")
print_str(100)
print("print_str(10000)")
print_str(10000)
print("print_str(1000000)")
print_str(1000000)
if __name__ == "__main__":  
main()运行结果：　　print_str(100)
4950
print_str usedtime: 3.60012054443e-05s
print_str(10000)
49995000
print_str usedtime: 0.000550985336304s
print_str(1000000)
499999500000
print_str usedtime: 0.0614850521088s
main usedtime: 0.0623250007629s

　　说明：运行结果中的红色部分，都是运行计时的结果
　　

　　示例2：

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# blog.ithomer.net
import time, functools
def functools_wrapper(func):
@functools.wraps(func)
def wrapper(*args, **kwargs):
print("call from functools_wrapper...")
start = time.time()
result = func(*args, **kwargs)
print("%s usedtime: %ss" % (func.__name__, time.time() - start))
#         return func(*args, **kwargs)   
return result
return wrapper
@functools_wrapper
def functools_partial():
print(int('10'))        # 10
print(int('10', 2))     # 2
int2 = functools.partial(int, base=2)
print(int2('10'))       # 2
print(int2('1010'))     # 10
int2 = functools.partial(int, base=8)
print(int2('10'))       # 8
print(int2('1010'))     # 520
@functools_wrapper
def functools_reduce():
array = [1, 2, 3, 4, 5, 6]
result = reduce((lambda x,y:x*y), array)
print("result = %d" % result)           # 720
result = functools.reduce((lambda x,y:x*y), array)
print("result = %d" % result)            # 720
def main():
functools_partial()
functools_reduce()
if __name__ == "__main__":  
main()运行结果：　　call from functools_wrapper...
10
2
2
10
8
520
functools_partial usedtime: 2.00271606445e-05s
call from functools_wrapper...
result = 720
result = 720
functools_reduce usedtime: 1.21593475342e-05s


　　

　　参考推荐：
　　Python的functools模块

　　Python的functools