What are Python iterators and how do they work?

What are Python iterators and how do they work?

Python iterators are objects that allow you to traverse through a collection, like lists or tuples, without needing to know the underlying structure. They implement two methods: iter() and next().

Can you give me an example of creating a custom iterator?

Sure! Here's a simple example:

class MyIterator:
    def __init__(self, limit):
        self.limit = limit
        self.current = 0

    def __iter__(self):
        return self

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

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

What is the difference between an iterator and an iterable?

An iterable is an object that can return an iterator, while an iterator is the object that actually iterates over the data. In Python, lists and tuples are iterables, and they can produce iterators.

How do I use the built-in iter() and next() functions?

You can use iter() to create an iterator from an iterable, and next() to get the next item from the iterator. For example:

my_list = [1, 2, 3]
my_iter = iter(my_list)
print(next(my_iter))  # Outputs: 1
print(next(my_iter))  # Outputs: 2