Reference library

Functions & basics

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

3 matches
Functions & basics easy

Benchmark list append vs comprehension in Python

This micro-benchmark compares the speed of building a list with a for loop and append versus a list comprehension, using the timeit module to get precise timings.

timeit benchmark performance
Python
import timeit

# Build a list of the first 1,000,000 integers using append in a loop
def append_loop(n=1_000_000):
    result = []
    for i in range(n):
        result.append(i)
    return result

# Build the same list using a list comprehension
def comprehension(n=1_000_000):
    return [i for i in range(n)]

if __n…
13 0 Open
Functions & basics easy

How to Compare Two Implementations with timeit in Python

Measure and compare the execution time of iterative vs recursive factorial functions using the timeit module.

timeit benchmark performance
Python
import timeit

def factorial_iterative(n):
    result = 1
    for i in range(2, n + 1):
        result *= i
    return result

def factorial_recursive(n):
    if n == 0:
        return 1
    return n * factorial_recursive(n - 1)

if __name__ == "__main__":
    n = 10
    iterations = 10000

    iterative_time = timeit…
13 0 Open
Functions & basics easy

Profile Python functions with cProfile

Profile a Python program with cProfile, capture the stats in memory, and print a sorted performance report.

cprofile performance profiling
Python
import cProfile
import pstats
import io


def slow_function():
    total = 0
    for i in range(100000):
        total += i ** 2
    return total


def medium_function():
    return sum(range(10000))


def fast_function():
    return sum(range(100))


def main():
    result1 = slow_function()
    result2 = medium_func…
11 0 Open

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Functions & basics — Python code examples

What you will find here

This page collects functions & basics snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.

Samples vs tutorials and challenges

Samples are quick reference — one concept per page. For step-by-step teaching, use our Python tutorials. To test yourself, try quizzes or coding challenges. Clean up style with the Python formatter.