Reference library

Functions & basics

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

3 matches

How to Count Items with Default Parameters in Python

Define a Python function that prints each item with a running counter, using default parameters to allow custom start values and step increments.

functions default-parameters loops

Python

def count_items(items, start=0, step=1):
    """Count items in a list with configurable start value and step."""
    count = start
    for item in items:
        print(f"{count}: {item}")
        count += step

if __name__ == "__main__":
    fruits = ["apple", "banana", "cherry"]
    print("Default parameters (start=0…

11 0 Open

Functions & basics easy

How to Create a Timing Decorator in Python

A Python decorator that measures and prints the execution time of any function using time.perf_counter.

decorator timing perf_counter

Python

import time
from functools import wraps


def timing_decorator(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        start = time.perf_counter()
        result = func(*args, **kwargs)
        end = time.perf_counter()
        elapsed = end - start
        print(f"{func.__name__} took {elapsed:.6f} seconds"…

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

Browse by section

Each section groups closely related Python snippets.