Lists

Creating & changing

A list holds items in order and you can change it after creation — add, remove, or edit elements.

fruits = ["apple", "banana", "cherry"]
fruits.append("date")
fruits.insert(1, "kiwi")
fruits.remove("banana")
print(fruits)

Output:

['apple', 'kiwi', 'cherry', 'date']

Indexing & slicing

Negative indices count from the end. Slicing [start:stop:step] pulls a sub-list without a loop.

nums = [10, 20, 30, 40, 50]
print(nums[-1])      # 50
print(nums[1:4])     # [20, 30, 40]
print(nums[::-1])    # [50, 40, 30, 20, 10]

List methods

Common methods: sort(), reverse(), pop(), extend(), index(), count(). Most mutate the list in place and return None.

sort() vs sorted()

sorted(nums) returns a new sorted list; nums.sort() sorts in place and returns None — a classic beginner bug.