What are Python iterators and how do they work with built-in functions?

What are Python iterators and how do they work with built-in functions?

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(). Built-in functions like sum(), map(), and filter() can work with iterators to process data efficiently.

Can you give me an example of using an iterator with the map function?

Sure! Here's an example: You can create a list of numbers and use the map() function to apply a function to each item. For instance:

numbers = [1, 2, 3, 4]
iterator = iter(numbers)
result = list(map(lambda x: x * 2, iterator))
print(result)  # Output: [2, 4, 6, 8]

What about using iterators with the filter function?

Great question! You can use filter() to filter items from an iterator based on a condition. For example:

numbers = [1, 2, 3, 4, 5]
iterator = iter(numbers)
result = list(filter(lambda x: x % 2 == 0, iterator))
print(result)  # Output: [2, 4]

Are there any performance benefits to using iterators?

Yes, using iterators can be more memory efficient, especially with large datasets, because they generate items on-the-fly rather than storing them all in memory at once.