Python Lists in Depth

The Swiss Army Knife of Data

A List is Python's most flexible built-in data structure. It allows you to store multiple items in a specific order inside a single variable. Lists are mutable, meaning you can change them after they are created.

inventory = ["Sword", "Shield", "Health Potion"]

# Modifying an item by index
inventory[1] = "Magic Shield"

Essential List Methods

• append(item): Slaps a new item onto the very end of the list.
• insert(index, item): Squeezes a new item into a specific position.
• pop(): Removes and returns the last item (great for building stacks/queues).
• remove(item): Finds the first matching item and deletes it.
• sort(): Sorts the list alphabetically or numerically in place.

List Comprehensions: Python Magic

List comprehensions let you create a new list based on an existing one in just a single line of highly readable code. It combines a for loop and an if statement elegantly.

prices = [10, 20, 30, 40, 50]

# Traditional way:
# discounted = []
# for p in prices:
#     if p > 25:
#         discounted.append(p * 0.9)

# Pythonic way (Comprehension):
discounted = [p * 0.9 for p in prices if p > 25]