Skip to main content

24. Tuples

1. Introduction​

A tuple is an ordered collection of items, similar to a list.
The key difference is that tuples are immutable — once created, their elements cannot be changed.

Tuples are often used when you want to group data that should not change.

2. Creating Tuples​

Tuples use parentheses ():

numbers = (1, 2, 3)
fruits = ("apple", "banana", "cherry")
mixed = (1, "hello", 3.14, True)

A tuple with one item needs a trailing comma:

single = (5,)
print(type(single))  # <class 'tuple'>

3. Accessing Elements​

Like lists, tuples use indexes:

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

4. Immutability of Tuples​

Tuples cannot be changed after creation:

colors = ("red", "green", "blue")
# colors[0] = "yellow"  # ❌ TypeError

But you can reassign the variable to a new tuple:

colors = ("yellow", "green", "blue")

5. Tuple Operations​

  • Concatenation:
a = (1, 2)
b = (3, 4)
print(a + b)  # (1, 2, 3, 4)
  • Repetition:
print(("hi",) * 3)  # ('hi', 'hi', 'hi')
  • Membership:
print(2 in (1, 2, 3))  # True

6. Tuple Slicing​

numbers = (10, 20, 30, 40, 50)
print(numbers[1:3])   # (20, 30)
print(numbers[:3])    # (10, 20, 30)
print(numbers[::-1])  # (50, 40, 30, 20, 10)

7. Tuple Methods​

Tuples have only two methods (since they are immutable):

nums = (1, 2, 2, 3)
print(nums.count(2))  # 2
print(nums.index(3))  # 3

8. Nested Tuples​

Tuples can contain other tuples:

nested = ((1, 2), (3, 4), (5, 6))
print(nested[1][0])  # 3

9. Packing and Unpacking​

You can pack values into a tuple and unpack them into variables:

person = ("Alice", 25, "Engineer")

name, age, job = person
print(name)  # Alice
print(age)   # 25
print(job)   # Engineer

10. When to Use Tuples​

  • When you need immutable data.
  • When you want to use a collection as a dictionary key (lists cannot be keys, but tuples can).
  • For grouping related items together, like (latitude, longitude).

11. Next Steps​

✅ You now understand tuples: how to create them, access them, and why immutability is important.
In the next chapter, we’ll explore sets, which are collections of unique items.