python __call__ 函数
__call__
Python中有一个有趣的语法,只要定义类型的时候,实现__call__函数,这个类型就成为可调用的。
换句话说,我们可以把这个类型的对象当作函数来使用,相当于 重载了括号运算符。
class g_dpm(object):
def __init__(self, g):
self.g = g
def __call__(self, t):
return (self.g*t**2)/2
计算地球场景的时候,我们就可以令e_dpm = g_dpm(9.8),s = e_dpm(t)。
-
-
class Animal(object):
-
def __init__(self, name, legs):
-
self.name = name
-
self.legs = legs
-
self.stomach = []
-
-
def __call__(self,food):
-
self.stomach.append(food)
-
-
def poop(self):
-
if len(self.stomach) > 0:
-
return self.stomach.pop(0)
-
-
def __str__(self):
-
return 'A animal named %s' % (self.name)
-
-
cow = Animal('king', 4) #We make a cow
-
dog = Animal('flopp', 4) #We can make many animals
-
print 'We have 2 animales a cow name %s and dog named %s,both have %s legs' % (cow.name, dog.name, cow.legs)
-
print cow #here __str__ metod work
-
-
#We give food to cow
-
cow('gras')
-
print cow.stomach
-
-
#We give food to dog
-
dog('bone')
-
dog('beef')
-
print dog.stomach
-
-
#What comes inn most come out
-
print cow.poop()
-
print cow.stomach #Empty stomach
-
-
'''-->output
-
We have 2 animales a cow name king and dog named flopp,both have 4 legs
-
A animal named king
-
['gras']
-
['bone', 'beef']
-
gras
-
[]
-
'''
-