Build a Basic Python Iterator

Question

How would one create an iterative function (or iterator object) in python?

Answer 1

I see some of you doing return self in __iter__. I just wanted to note that __iter__ itself can be a generator (thus removing the need for __next__ and raising StopIteration exceptions)

class range:
  def __init__(self,a,b):
    self.a = a
    self.b = b
  def __iter__(self):
    i = self.a
    while i < self.b:
      yield i
      i+=1

Of course here one might as well directly make a generator, but for more complex classes it can be useful.