Add iterator behavior to your classes : Iterator Behavior « Buildin Function « Python

1. Python
2. Buildin Function
3. Iterator Behavior

Add iterator behavior to your classes

#Define a __iter__() method which returns an 
#object with a next() method. If the class defines next(), then __iter__() can just 
#return self:

class Reverse:
    "Iterator for looping over a sequence backwards"
    def __init__(self, data):
        self.data = data
        self.index = len(data)
    def __iter__(self):
        return self
    def next(self):
        if self.index == 0:
            raise StopIteration
        self.index = self.index - 1
        return self.data[self.index]

for char in Reverse('spam'):
     print char


           
       

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