Module 9: Tuples

In this module, we will learn about Tuples. A tuple is used to store multiple items in a single variable, similar to a list. However, tuples have some key differences.

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9.1 Introduction to Tuples

• A tuple is created using parentheses or round brackets (( )) with items separated by commas.
• Tuples are Immutable. This means once a tuple is created, you cannot change, add, or remove its items.
• Tuples are faster and use less memory than lists.

# Creating tuples
coordinates = (10.5, 20.8)
colors = ("red", "green", "blue")
single_item_tuple = (5,) # Note: You must add a trailing comma for a single-item tuple

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9.2 Tuple Operations

Since tuples cannot be changed, they support limited operations.

Accessing Items:

fruits = ("apple", "banana", "mango")
print(fruits[0])  # Output: apple
print(fruits[-1]) # Output: mango

Trying to modify a tuple:

# fruits[1] = "grapes" # This will throw a TypeError!

Joining Tuples (Concatenation):

You can combine two tuples to create a new one:

t1 = (1, 2)
t2 = (3, 4)
t3 = t1 + t2
print(t3) # Output: (1, 2, 3, 4)

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9.3 Tuple Methods

Tuples only have two built-in methods because their values cannot be changed:

1. count(): Counts how many times a specific value appears in the tuple.
2. index(): Returns the position (index) of the first occurrence of a specific value.

numbers = (1, 2, 3, 2, 4, 2, 5)

print(numbers.count(2)) # Output: 3 (number 2 appears three times)
print(numbers.index(4)) # Output: 4 (number 4 is at index 4)

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9.4 Tuple vs List (Key Differences)

Understanding when to use a list and when to use a tuple is very important:

Feature	List	Tuple
Syntax	Uses square brackets [ ].	Uses round brackets ( ).
Mutability	Mutable (can be changed).	Immutable (cannot be changed).
Speed	Slower performance.	Faster performance.
Memory	Uses more memory.	Uses less memory.
Use Case	Use when data needs to change.	Use for constant values (data that never changes).

Real-World Example:

• The names of the days of the week (Monday, Tuesday...) never change. We should store them in a Tuple.
• Items in a user's shopping cart change frequently. We should store them in a List.