python 闭包初识

 def func_100(val):
     passline = 60
     if val >= passline:
         print('pass')
     else:
         print('failed')

 def func_150(val):
     passline = 90
     if val >= passline:
         print('pass')
     else:
         print('failed')

 func_100(89)
 func_150(89)

 输出：pass
          failed

未使用闭包

def set_passline(passline):
    def cmp(val):
        if val >= passline:
            print('pass')
        else:
            print('failed')
    return cmp

f_100 = set_passline(60)
f_150 = set_passline(90)
f_100(89)
f_150(89)

输出：pass
         failed

使用闭包

 def my_sum(*arg):
     if len(arg) == 0:
         return 0
     for val in arg:
         if not isinstance(val, int):
             return 0
     return sum(arg)

 def my_average(*arg):
     if len(arg) == 0:
         return 0
     for val in arg:
         if not isinstance(val, int):
             return 0
     return sum(arg)/len(arg)

 print(my_sum(1, 2, 3, 4, 5))
 print(my_sum(1, 2, 3, 4, 5, ''))
 print(my_average(1, 2, 3, 4, 5))
 print(my_average())

 输出：15
          0
          3
          0

未使用闭包

 def my_sum(*arg):
     return sum(arg)

 def my_average(*arg):
     return sum(arg)/len(arg)

 def dec(func):
     def in_dec(*arg):
         if len(arg) == 0:
             return 0
         for val in arg:
             if not isinstance(val, int):
                 return 0
         return func(*arg)
     return in_dec

 my_sum = dec(my_sum)
 my_average = dec(my_average)

 print(my_sum(1, 2, 3, 4, 5))
 print(my_sum(1, 2, 3, 4, 5, ''))
 print(my_average(1, 2, 3, 4, 5))
 print(my_average())

 输出：15
          0
          3
          0

使用闭包

闭包作用

1：封装

2：代码复用