Reference library

Functions & basics

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

4 matches

Add Type Hints to Function Parameters and Return in Python

Add type hints to function parameters and return values in Python for clearer, more maintainable code using the typing module.

type-hints typing annotations

Python

from typing import List, Optional, Dict


def average(numbers: List[float]) -> float:
    return sum(numbers) / len(numbers)


def full_name(first: str, last: Optional[str] = "") -> str:
    return f"{first} {last}".strip()


def build_user(name: str, age: int, email: Optional[str] = None) -> Dict[str, object]:
    us…

16 0 Open

Functions & basics easy

How to Write a Context Manager Class in Python

Define a class with __enter__ and __exit__ to manage file resources safely using the with statement.

context-manager with-statement resource-management

Python

class FileReader:
    def __init__(self, filename, mode="r"):
        self.filename = filename
        self.mode = mode
        self.file = None

    def __enter__(self):
        self.file = open(self.filename, self.mode)
        return self.file

    def __exit__(self, exc_type, exc_val, exc_tb):
        if self.file…

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

Functions & basics easy

Write a Pure Function Without Side Effects in Python

Defines a pure function that adds one to a number without modifying external state.

pure functions side effects functions

Python

def add_one(x: int) -> int:
    """Adds 1 to the input without modifying any external state."""
    return x + 1

if __name__ == "__main__":
    original = 5
    result = add_one(original)
    print(f"Original: {original}")
    print(f"Result: {result}")
    print(f"Original unchanged: {original}")

12 0 Open

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