Lists and Tuples — Python Tutorial

Lists and tuples both hold an ordered collection of items, and both support indexing and slicing the same way. The difference that matters is mutability: a list can change after it's created; a tuple can't.

Lists

fruits = ["apple", "banana", "cherry"]
print(fruits[0])     # apple
print(fruits[-1])    # cherry -- negative indices count from the end

Lists are mutable — you can add, remove, and change items in place:

fruits.append("date")        # add to the end
fruits.insert(1, "apricot")  # insert at a specific position
fruits.remove("banana")      # remove by value
fruits[0] = "avocado"        # replace by index
print(len(fruits))           # current number of items

Slicing

Slicing pulls out a sub-sequence with start:stop (stop is exclusive):

numbers = [0, 1, 2, 3, 4, 5]
print(numbers[1:4])    # [1, 2, 3]
print(numbers[:3])     # [0, 1, 2] -- from the start
print(numbers[3:])     # [3, 4, 5] -- to the end
print(numbers[::2])    # [0, 2, 4] -- every second item
print(numbers[::-1])   # [5, 4, 3, 2, 1, 0] -- reversed

Slicing always returns a new list, leaving the original untouched — a common way to make a copy is numbers[:].

Tuples

point = (3, 4)
print(point[0])   # 3

Tuples look and behave like lists for reading, but trying to change one fails immediately:

point[0] = 5
# TypeError: 'tuple' object does not support item assignment

That immutability is the whole point. Use a tuple when a value is meant to be fixed once created — coordinates, an RGB color, a database row — signaling to anyone reading the code (and to Python itself) that it shouldn't change. A single-item tuple needs a trailing comma to be recognized as one: (5,), not (5) (which is just the number 5 in parentheses).

Unpacking

Both lists and tuples support unpacking directly into named variables:

point = (3, 4)
x, y = point
print(x, y)   # 3 4

first, *rest = [1, 2, 3, 4]
print(first)  # 1
print(rest)   # [2, 3, 4]

The *rest syntax collects "everything else" into a list — handy for peeling off the first item (or first few) without manual slicing.

Which one to use

Default to a list for any collection you expect to grow, shrink, or reorder. Reach for a tuple when the collection's size and contents are fixed by design — function return values with multiple parts, coordinate pairs, or anything used as a dictionary key (which must be immutable, and so can't be a list — but can be a tuple).