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Python Code Samples

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8 matches
Lists & loops easy

How to unzip a list of pairs into two lists in Python

Split a list of (a, b) tuples into two separate lists by iterating with a for loop and appending each element to its own output list.

lists tuples loops
Python
def unzip(pairs):
    """Split a list of (a, b) pairs into two separate lists."""
    if not pairs:
        return [], []
    
    firsts = []
    seconds = []
    for a, b in pairs:
        firsts.append(a)
        seconds.append(b)
    
    return firsts, seconds


if __name__ == "__main__":
    pairs = [(1, 'a'), (…
14 0 Open
Functions & basics easy

How to Return Multiple Values from a Python Function

This code demonstrates how a Python function can return multiple values as a tuple, and how to unpack that tuple into individual variables.

functions tuple return-values
Python
def get_user_stats(name, score, level):
    """Return multiple values as a tuple."""
    return name, score, level

if __name__ == "__main__":
    result = get_user_stats("Alice", 95, 3)
    print(result)
    print(type(result))
    
    # Unpacking into individual variables
    player_name, player_score, player_level…
16 0 Open
Errors & debugging easy

How to Return Success or Error as a Tuple in Python (Result Type Pattern)

Use a (bool, value) tuple as a lightweight Result type to return either a successful result or a descriptive error message from a Python function.

result type error handling tuple unpacking
Python
def divide(dividend: float, divisor: float) -> tuple[bool, float | str]:
    """Return (True, result) on success, (False, error_message) on failure."""
    if divisor == 0:
        return False, "Error: Division by zero"
    return True, dividend / divisor


if __name__ == "__main__":
    # Success case
    success, r…
10 0 Open
Dictionaries & sets easy

How to Merge Two Dictionaries in Python with the Spread Operator

Merge two Python dictionaries into one new dict using the ** unpacking (spread) operator, with later keys overriding earlier ones.

dicts merge spread-operator
Python
def merge_two_dicts(dict1: dict, dict2: dict) -> dict:
    """Merge two dictionaries using the spread operator pattern."""
    # The ** operator unpacks key-value pairs, later keys overwrite earlier ones
    merged = {**dict1, **dict2}
    return merged


if __name__ == "__main__":
    # Example usage with overlapping…
15 0 Open
Dictionaries & sets easy

How to merge dictionaries and sets in Python

Merges multiple dictionaries with the ** unpacking operator and combines sets using union operations into a single structure.

dict-merge set-union unpacking
Python
def merge_dictionaries_and_sets(school_dict, teacher_dict, course_dict, student_sets):
    """
    Merges multiple dictionaries and sets into a single combined structure.
    Demonstrates dict unpacking and set union operations.
    """
    # Merge all dictionaries using the unpacking operator (Python 3.9+)
    merged…
12 0 Open
Comprehensions & generators easy

How to Use starmap() to Unpack Tuple Arguments in Python

Use itertools.starmap to apply a function to each tuple in an iterable, unpacking tuple elements as separate arguments and returning an iterator of results.

itertools starmap generators
Python
from itertools import starmap

def multiply(a, b):
    return a * b

if __name__ == "__main__":
    pairs = [(2, 3), (4, 5), (6, 7), (8, 9)]
    results = list(starmap(multiply, pairs))
    print(results)
14 0 Open
Data pipelines & processing easy

Attach Source File Metadata to Records in Python

Add a source filename field to each record in a list by merging a new key into every dictionary using a dict unpacking comprehension.

lineage metadata dict-unpacking
Python
from pathlib import Path
import json

def attach_source_metadata(records, source_file):
    """Attach source filename metadata to each record."""
    return [
        {**record, "source": Path(source_file).name}
        for record in records
    ]

if __name__ == "__main__":
    source = "/data/raw/customers.csv"
    …
15 0 Open
Testing & modern typing easy

How to Merge TypedDicts in Python

Merge two TypedDict dictionaries with type-aware logic using NotRequired, **kwargs unpacking, and safe key updates.

typing typeddict dict
Python
from typing import TypedDict, NotRequired, merge  # hypothetical

class User(TypedDict):
    name: str
    email: NotRequired[str]
    age: NotRequired[int]

def merge_users(base: User, **overrides: User) -> User:
    """Merge two user dicts with typing-aware logic."""
    result: User = dict(base)
    for key, value …
13 0 Open

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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.