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Python Code Samples

Easy snippets you can copy, study, and run in the browser editor.

5 matches
Lists & loops easy

Enumerate a Python List with a Custom Start Index

Iterate over a list with an index that starts at a custom value (like 5) using Python's built-in enumerate() function with the start parameter.

enumerate iteration loops
Python 
fruits = ["apple", "banana", "cherry", "date"]

for index, fruit in enumerate(fruits, start=5):
    print(f"{index}: {fruit}")
15 0 Open
Lists & loops easy

How to Swap Two Indices in a Python List

Swap two elements at given indices in a Python list using simultaneous assignment, then return the modified list.

list swap indexing
Python 
def swap_indices(lst, i, j):
    lst[i], lst[j] = lst[j], lst[i]
    return lst

if __name__ == "__main__":
    my_list = [10, 20, 30, 40, 50]
    print("Original list:", my_list)
    swapped = swap_indices(my_list, 1, 3)
    print("After swapping indices 1 and 3:", swapped)
14 0 Open
Database scaling & optimization easy

Database indexing and query timing optimization in Python

Create SQLite indexes and time query performance to measure speedup for large table lookups in Python.

sqlite indexing query optimization
Python 
import sqlite3
import time


def time_query(db_path, query, params=()):
    conn = sqlite3.connect(db_path)
    conn.execute("PRAGMA journal_mode = WAL")
    start = time.perf_counter()
    result = conn.execute(query, params).fetchall()
    elapsed = time.perf_counter() - start
    conn.close()
    return result, ela…
14 0 Open
Database scaling & optimization easy

How to Create a Database Helper Class for Beginners in Python

Build a beginner-friendly SQLite helper class with indexing and batch inserts to optimize database queries in Python.

sqlite database indexing
Python 
import sqlite3


class DatabaseHelper:
    def __init__(self, db_path):
        self.connection = sqlite3.connect(db_path)
        self.cursor = self.connection.cursor()

    def create_table_with_index(self, table_name, columns, indexed_column):
        columns_sql = ", ".join(f"{name} {dtype}" for name, dtype in col…
13 0 Open
Database scaling & optimization easy

How to Speed Up Column Lookups with DataFrame Index in Python

Use pandas set_index to make repeated column value lookups O(1)-style fast instead of scanning the whole DataFrame each time.

pandas indexing performance
Python 
import pandas as pd

# Mock dataset with duplicate customer IDs
data = {"customer_id": [101, 102, 103, 101, 104, 102],
        "order_amount": [250.0, 85.5, 300.0, 175.25, 420.0, 95.75]}

df = pd.DataFrame(data)
df = df.set_index("customer_id")

# Simulated lookup request
search_id = 102

# Fast index-based lookup (no…
15 0 Open

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Copy-ready Python snippets for learners and developers

PythonSkillset code samples are short, focused examples organised by topic and difficulty. Every snippet is server-rendered HTML — readable by search engines and easy to copy. Open any sample, read the notes, copy the code, then press Try in editor to run it in the browser with Pyodide.

How to use this library

  1. Pick a topic section — strings, lists, files, functions, and more
  2. Open a sample, read How it works, and copy the code block
  3. Run it in the IDE, tweak values, then take a related quiz or tutorial lesson

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