Iterator function in Python

PythonProgrammingServer Side Programming

Explanation

Iterator is an object in python that implements iteration protocol. Tuples,lists,sets are called inbuilt iterators in Python.There are two types of method in iteration protocol.

__iter__() : This method is called when we initialize an iterator and this must return an object which consist next() or __next__()(in Python 3) method.

next() or __next__() (in Python 3) : This method should returns the next element from a iteration sequence.When an iterator is used with a for loop the for loop directly call the next() on the iterator object.

Example Code

# creating a custom iterator
class Pow_of_Two:
def __init__(self, max = 0):
   self.max = max
   def __iter__(self):
      self.n = 0
      return self
      def __next__(self):
         if self.n <= self.max:
         result = 2 ** self.n
      self.n += 1
      return result
   else:
      raise StopIteration("Message")
      a = Pow_of_Two(4)
      i = iter(a)
print(i.__next__())
print(next(i))
print(next(i))
print(next(i))
print(next(i))
print(next(i))

Output

1
2
4
8
16
StopIteration error will be raised
raja
Published on 26-Sep-2018 12:50:26
Advertisements