How can I implement iterator patterns in Python?

How can I implement iterator patterns in Python?

You can implement iterator patterns in Python by defining an __iter__() method and a __next__() method in your class.

Can you give me an example of a custom iterator?

Sure! Here's a simple example of a custom iterator that iterates over a list of numbers:

class NumberIterator:
    def __init__(self, numbers):
        self.numbers = numbers
        self.index = 0

    def __iter__(self):
        return self

    def __next__(self):
        if self.index < len(self.numbers):
            result = self.numbers[self.index]
            self.index += 1
            return result
        else:
            raise StopIteration

How do I use this iterator in a loop?

You can use the custom iterator in a loop like this:

numbers = [1, 2, 3, 4, 5]
iterator = NumberIterator(numbers)

for number in iterator:
    print(number)
``` This will print each number in the list.