How can I create custom iterators in Python?

How can I create custom iterators in Python?

You can create a custom iterator by defining a class with the __iter__() and __next__() methods. Would you like an example?

Yes, please provide an example.

Here's a simple example:

class Countdown:
    def __init__(self, start):
        self.current = start

    def __iter__(self):
        return self

    def __next__(self):
        if self.current < 0:
            raise StopIteration
        else:
            self.current -= 1
            return self.current + 1

This creates a countdown iterator that counts down from a specified start value.

How do I use this iterator in a loop?

You can use it in a loop like this:

for number in Countdown(5):
    print(number)

This will print numbers from 5 to 1.