Introduction to Tuples

Overview

• This lecture introduces tuples in Python.
• Key topics include:
  • What is a tuple?
  • Tuple with one item
  • Length of a tuple
  • Tuple Constructor

What is a Tuple?

• A tuple is a collection of items that are:
  • Indexed: Each item has an index (0, 1, 2, ...).
  • Ordered: The order of items remains the same.
  • Immutable: Once created, a tuple cannot be changed.

Syntax

• Syntax to create a tuple: tuple_name = (item1, item2, item3, ...)
• Tuples are defined using round brackets (parentheses), while lists use square brackets.

Example

• Creating a tuple of cars: cars = ('Audi', 'Mercedes', 'BMW')
• Accessing items by index:
  • cars[0] returns 'Audi'
  • cars[1] returns 'Mercedes'
  • cars[2] returns 'BMW'

Important Terms

1. Indexed: Access items using their index.
2. Immutable:
   • Attempting to change an item results in a TypeError.
   • Example: cars[0] = 'Ferrari'
3. Ordered: The order of items is maintained.
4. Duplicates: Tuples can have duplicate items.
   • Example: cars = ('Audi', 'Mercedes', 'Mercedes', 'BMW')

Tuple with One Item

• To create a tuple with one item, a comma is mandatory.
• Syntax: single_item_tuple = (item,)
• Example without a comma results in a string instead of a tuple: car = ('Audi')

Length of a Tuple

• Use the len() function to determine the length of a tuple.
• Example: len(cars)
  • Returns the number of items in the tuple.

Tuple Constructor

• An alternative way to create a tuple is using the tuple constructor: cars = tuple(('Audi', 'Mercedes', 'BMW'))
• This also results in the tuple being created with the specified items.

Conclusion

• The lecture covered the basics of tuples, including their properties, creation, and usage.
• Further topics will be discussed in the next session.