A list in Python is a versatile and widely used data structure. It allows you to store multiple items in a single variable, even with mixed data types.

In this tutorial, you’ll learn:

• What a list is

• How to create and access list elements

• Common list operations

• List methods

• Nested lists

• Tips and common pitfalls

What Is a List?

A list is a collection that is:

• Ordered

• Mutable (can be changed)

• Allows duplicate values

Creating a List

fruits = ["apple", "banana", "cherry"]
numbers = [1, 2, 3, 4, 5]
mixed = ["hello", 42, 3.14, True]

Accessing List Elements

List elements are zero-indexed (the first element is at index 0).

fruits = ["apple", "banana", "cherry"]
print(fruits[0])  # apple
print(fruits[-1]) # cherry (last element)

✏️ Modifying a List

✅ Changing Items

fruits[1] = "blueberry"
print(fruits)  # ['apple', 'blueberry', 'cherry']

✅ Adding Items

• append() adds to the end:

  fruits.append("orange")
  

• insert() adds at a specific position:

  fruits.insert(1, "grape")
  

✅ Removing Items

• remove() deletes a specific item:

  fruits.remove("banana")
  

• pop() removes by index (default is last):

  fruits.pop()
  

• del deletes by index:

  del fruits[0]
  

• clear() empties the list:

  fruits.clear()
  

Looping Through Lists

for fruit in fruits:
    print(fruit)

With index:

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

Useful List Methods

Slicing Lists

Extract a portion of the list:

fruits = ["apple", "banana", "cherry", "orange", "kiwi"]
print(fruits[1:4])  # ['banana', 'cherry', 'orange']
print(fruits[:3])   # ['apple', 'banana', 'cherry']
print(fruits[-2:])  # ['orange', 'kiwi']

Nested Lists

Lists within lists:

matrix = [
  [1, 2, 3],
  [4, 5, 6]
]

print(matrix[0][1])  # 2

Example: Grocery List Program

groceries = []

while True:
    item = input("Add item (or 'done'): ")
    if item == 'done':
        break
    groceries.append(item)

print("Your grocery list:")
for item in groceries:
    print("- " + item)

Tips for Working with Lists

• Use copy() to clone a list instead of =, which shares references.

• Use list comprehensions for quick transformations:

  squares = [x**2 for x in range(5)]
  

• Lists can hold any type of object, including other lists and functions.

⚠️ Common Pitfalls

Summary

What’s Next?

After learning about lists, explore:

• Tuples (immutable lists)

• List comprehensions

• Dictionaries (key-value pairs)

• Functions and how to pass lists as arguments