Python Lists

🐍 Python Lists — Full Tutorial

A Python Lists is an ordered, changeable (mutable) collection that can store multiple items of different data types.

Lists are written using square brackets []:

my_list = ["Apple", "Banana", "Cherry"]

 1. Creating a List

numbers = [1, 2, 3, 4, 5]
mixed = [10, "Hello", True, 5.5]
empty_list = []

 2. Accessing List Items (Indexing)

Indexes start from 0:

Apple Banana Cherry
0 1 2

fruits = ["Apple", "Banana", "Cherry"]

print(fruits[0]) # Apple
print(fruits[2]) # Cherry

Negative indexing:

print(fruits[-1]) # Cherry
print(fruits[-2]) # Banana

 3. Slicing Lists

Extract a portion of the list:

fruits = ["Apple", "Banana", "Cherry", "Mango", "Orange"]

print(fruits[1:4]) # [‘Banana’, ‘Cherry’, ‘Mango’]
print(fruits[:3]) # [‘Apple’, ‘Banana’, ‘Cherry’]
print(fruits[2:]) # [‘Cherry’, ‘Mango’, ‘Orange’]

 4. Modifying List Items

Lists are mutable, meaning you can change values.

fruits = ["Apple", "Banana", "Cherry"]
fruits[1] = "Kiwi"print(fruits) # [‘Apple’, ‘Kiwi’, ‘Cherry’]

 5. Adding Items to a List

Method Action
append() Adds item at end
insert() Adds item at specific index
extend() Adds multiple items

Examples:

fruits = ["Apple", "Banana"]

fruits.append(“Orange”) # Add at end
fruits.insert(1, “Kiwi”) # Add at position
fruits.extend([“Mango”, “Grapes”]) # Add multiple

print(fruits)

6. Removing Items

Method Action
remove() remove by value
pop() remove by index (default removes last item)
del delete using index or whole list
clear() empty the list

Examples:

list1 = ["Apple", "Banana", "Cherry"]

list1.remove(“Banana”)
list1.pop(0)
del list1[0]
list1.clear()

 7. Looping Through a List

fruits = ["Apple", "Banana", "Cherry"]

for x in fruits:
print(x)

With index:

for i in range(len(fruits)):
print(i, fruits[i])

8. Checking if Item Exists

fruits = ["Apple", "Banana"]

print(“Apple” in fruits) # True
print(“Kiwi” not in fruits) # True

 9. Sorting Lists

numbers = [5, 3, 9, 1]
numbers.sort() # ascending
numbers.sort(reverse=True) # descendingprint(numbers)

Sorting strings:

fruits = ["Banana", "Apple", "Cherry"]
fruits.sort()print(fruits)

 10. Copying Lists (Important)

list1 = [1, 2, 3]
list2 = list1.copy()print(list2)

or:

list2 = list1[:]

 11. Joining Lists

list1 = [1, 2, 3]
list2 = [4, 5, 6]combined = list1 + list2

or:

list1.extend(list2)

 12. Built-in List Functions

Function Purpose
len() count items
max() largest value
min() smallest value
sum() sum of numbers

Example:

numbers = [10, 20, 30]
print(len(numbers)) # 3
print(max(numbers)) # 30
print(min(numbers)) # 10
print(sum(numbers)) # 60

 13. List Comprehension (Advanced but important)

A short way to create lists:

numbers = [x for x in range(10)]
print(numbers)

Filter example:

even = [x for x in range(10) if x % 2 == 0]
print(even)

⭐ Mini Project Example


 

You may also like...