Python Lists and Tuples
Introduction
Python provides several built-in data types to store collections of data. Two of the most commonly used are Lists and Tuples. Both allow you to store multiple values in a single variable, making programs more organized and efficient.
Although lists and tuples look similar, they have an important difference:
Lists are mutable (can be changed).
Tuples are immutable (cannot be changed after creation).
Understanding when to use a list and when to use a tuple is an essential Python skill.
What is a List?
A List is an ordered collection of items enclosed in square brackets [ ].
Lists can store:
Numbers, Strings, Boolean values, Objects, Mixed data types
Syntax
list_name = [item1, item2, item3]
Example:
fruits = [“Apple”, “Banana”, “Mango”]
print(fruits)
output:
[‘Apple’, ‘Banana’, ‘Mango’]
properties of Lists
Ordered
Mutable (can be modified)
Allows duplicate values
Can store different data types
Supports indexing and slicing
Example:
data = [10, “Python”, 3.14, True]
print(data)
Output:
[10, ‘Python’, 3.14, True]
Accessing List Elements
Using positive Indexing
fruits = [“Apple”, “Banana”, “Mango”]
print(fruits[0])
print(fruits[2])
Output:
Apple
Mango
Using Negative Indexing
print(fruits[-1])
output:
Mango
List Slicing
numbers = [10,20,30,40,50]
print(numbers[1:4])
Output
[20, 30, 40]
Modifying a List
fruits = [“Apple”,”Banana”,”Mango”]
fruits[1] = “Orange”
print(fruits)
output:
[‘Apple’, ‘Orange’, ‘Mango’]
List Methods
append()
Adds an item to the end.
Example
numbers = [1,2,3]
numbers.append(4)
print(numbers)
output:
[1,2,3,4]
insert()
Adds an item at a specific position.
numbers.insert(1,100)
print(numbers)
output:
[1,100,2,3,4]
extend()
Adds multiple elements.
numbers.extend([5,6])
print(numbers)
output:
[1,100,2,3,4,5,6]
remove()
Removes a specified value.
numbers.remove(100)
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print(numbers)
output:
[1,2,3,4,5,6]
pop()
Removes an item by index.
numbers.pop(2)
print(numbers)
output:
[1,2,4,5,6]
clear()
Removes all items.
numbers.clear()
print(numbers)
output: []
sort()
Sorts the list.
marks = [45,12,90,32]
marks.sort()
print(marks)
output:
[12,32,45,90]
reverse()
Reverses the list.
marks.reverse()
print(marks)
output:
[90,45,32,12]
count()
Counts occurrences.
a = [1,2,2,3,2]
print(a.count(2))
output: 3
index()
Returns the first index of a value.
print(a.index(3))
output: 3
What is a Tuple?
A Tuple is an ordered collection enclosed in parentheses ( ).
Unlike lists, tuples cannot be modified after creation.
tuple_name = (item1, item2, item3)
Example:
colors = (“Red”,”Green”,”Blue”) print(colors)
output:
(‘Red’, ‘Green’, ‘Blue’)
Properties of Tuples
Ordered
Immutable
Allows duplicate values
Faster than lists
Supports indexing and slicing
Accessing Tuple Elements
colors = (“Red”,”Green”,”Blue”)
print(colors[0])
print(colors[-1])
output:
Red
Blue
Tuple Slicing
numbers = (10,20,30,40,50)
print(numbers[1:4])
Output:
(20,30,40)
Tuple Methods
Since tuples are immutable, they have only two built-in methods.
count()
numbers = (1,2,2,3,2)
print(numbers.count(2))
Output: 3
index()
print(numbers.index(3))
output: 3
Summary
List is a mutable collection enclosed in square brackets [ ].
Tuple is an immutable collection enclosed in parentheses ( ).
Both support indexing, slicing, and duplicate values.
Lists provide many methods for modifying data, while tuples offer only count() and index().
Use lists for data that changes and tuples for fixed, read-only data.
