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Functions & basics

Reusable building blocks — parameters, returns, scope, and clear function design.

3 matches

How to Convert a List to an Iterator in Python with iter()

This code converts a list into an iterator using the built-in iter() function and retrieves items sequentially with next(), handling exhaustion with StopIteration.

iter iterator built-in

Python

def main():
    # Original list
    fruits = ["apple", "banana", "cherry"]

    # Convert the list to an iterator using iter()
    fruit_iterator = iter(fruits)

    # Retrieve items one at a time with next()
    print(next(fruit_iterator))  # apple
    print(next(fruit_iterator))  # banana
    print(next(fruit_iterat…

12 0 Open

Functions & basics easy

How to Create an Iterator Class with Dunder Methods in Python

A minimal Counter class implementing __iter__ and __next__ to act as a self-iterating iterator, yielding numbers from start to end-1.

iterators dunder-methods class

Python

class Counter:
    def __init__(self, start=0, end=5):
        self.current = start
        self.end = end

    def __iter__(self):
        return self

    def __next__(self):
        if self.current >= self.end:
            raise StopIteration
        value = self.current
        self.current += 1
        return val…

13 0 Open

Functions & basics easy

How to Use Python's next() Builtin with a Default Sentinel Value

A wrapper function that returns the next item from an iterator, or a default sentinel value when the iterator is exhausted.

next iterator sentinel

Python

def get_next_or_default(iterator, default=None):
    """Return the next item from an iterator, or default if exhausted."""
    return next(iterator, default)


if __name__ == "__main__":
    fruits = iter(["apple", "banana", "cherry"])
    
    print(get_next_or_default(fruits))           # apple
    print(get_next_or…

14 0 Open

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