User-Defined Iterators : iter « Class « Python Tutorial

1. Python Tutorial
2. Class
3. iter

class Squares:
    def __init__(self, start, stop):   
        self.value = start - 1
        self.stop  = stop
    def __iter__(self):                
        return self
    def next(self):                    
        if self.value == self.stop:
            raise StopIteration
        self.value += 1
        return self.value ** 2


for i in Squares(1, 5):                
    print i,