Tuples and Their Immutability

A tuple is an ordered collection almost identical to a list in how you create and access it — with one defining difference: once created, a tuple can never be changed. No adding, removing, or reassigning individual elements.

Creating a Tuple

coordinates = (10, 20)
colors = ("red", "green", "blue")
mixed = ("Vishwas", 22, True)
single_item = ("apple",)   # the trailing comma is REQUIRED for a one-item tuple

Without the trailing comma, ("apple") is just the string "apple" wrapped in ordinary parentheses, NOT a tuple. The comma — not the parentheses — is what actually makes it a tuple.

Accessing Tuple Items

Indexing and slicing work exactly the same way as lists.

colors = ("red", "green", "blue")
print(colors[0])     # red
print(colors[-1])    # blue
print(colors[0:2])   # ('red', 'green')

Tuples Cannot Be Modified

colors = ("red", "green", "blue")
# colors[0] = "yellow"   # TypeError: 'tuple' object does not support item assignment
# colors.append("yellow") # AttributeError: tuples have no append() method

Lists vs Tuples — Side by Side

Tuple Unpacking

One of the most useful tuple features — assigning multiple variables from a tuple in a single line.

point = (4, 7)
x, y = point
print(x)   # 4
print(y)   # 7

# This is exactly how a function returns multiple values
def get_min_max(numbers):
    return min(numbers), max(numbers)

low, high = get_min_max([3, 8, 1, 9])
print(low, high)   # 1 9

Unpacking With *

numbers = (1, 2, 3, 4, 5)
first, *middle, last = numbers
print(first)    # 1
print(middle)   # [2, 3, 4]  — collected into a list
print(last)     # 5

Why Use a Tuple Instead of a List?

• Data integrity: guarantees the data can never accidentally be modified elsewhere in the program
• Dictionary keys: tuples (unlike lists) can be used as dictionary keys, since they are hashable
• Performance: tuples have a smaller memory footprint and are marginally faster to iterate over than lists

# A tuple as a dictionary key — only possible because tuples are immutable
locations = {
    (12.97, 77.59): "Bengaluru",
    (28.61, 77.21): "Delhi"
}
print(locations[(12.97, 77.59)])   # Bengaluru

Converting Between Lists and Tuples

my_list = [1, 2, 3]
my_tuple = tuple(my_list)   # (1, 2, 3)

back_to_list = list(my_tuple)   # [1, 2, 3]

Interview tip: "Why would you ever choose a tuple over a list?" is a near-guaranteed question — the strongest answer combines all three reasons: immutability for data safety, hashability for use as dict keys, and the minor performance edge, rather than giving just one.