Python中有趣在

 　　這篇文章主要介紹了Python中有趣在__call__函數,本文直接給出一個使用實例,以此來講解__call__函數的用法,需要的朋友可以參考下

　　Python中有一個有趣的語法，只要定義類型的時候，實現__call__函數，這個類型就成為可調用的。

　　換句話說，我們可以把這個類型的對象當作函數來使用，相當於 重載了括號運算符。

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1 2 3 4 5 class g_dpm(object): def __init__(self, g): self.g = g def __call__(self, t): return (self.g*t**2)/2

　　計算地球場景的時候，我們就可以令e_dpm = g_dpm(9.8)，s = e_dpm(t)。

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 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 [] '''