Course Content

Introduction to Python Video Course

1. Getting Started

First Steps Comments Simple Math Operations Grocery Calculation Capstone Recap

2. Variables and Types

Data Types Storing Data in Variables Variable Naming Rules Using Variables String Indexing and Length String Slicing and Concatenation Inventory Sorting Capstone Challenge Recap

3. Conditional Statements

Boolean Data Type Combining Conditions Challenge Membership Operators and Type Comparisons Conditional Expressions Capstone Challenge Recap

4. Other Data Types

Lists and List Methods Nested Lists Challenge Tuples and Tuple Methods Tuple Operations Challenge Dictionaries and Dictionary Methods Capstone Challenge Recap

5. Loops

For Loops While Loops Range Function Iterating Over Indexes Challenge Nested Loops Capstone Challenge Challenge Recap

6. Functions

Built-in Functions User Defined Functions Challenge Functions with no `return`Modifying Functions Capstone Challenge Recap

Nested Lists

A nested list in Python is a list that contains other sublists as its elements. This structure is particularly useful for grouping related items within a main list, where each sublist often shares common attributes or relationships.

To access elements within these sublists, indexing is used sequentially — meaning, we select the main list index first and then the sublist index. The following practical application and diagram provide a detailed look at how you can create and manage nested lists effectively.

Example Application

A customer in your grocery store has compiled a list of grocery items, where each item's details are stored in sublists under variable names.

We will help the customer access details from the milk sublist, add a new item, remove an existing item, and sort the entire grocery_list.

Let's start by creating a list first, and go step by step:


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# Define individual grocery items as lists containing details
bread = ["Bread", 4.80, 3, "Gluten Free"] # Item name, price, quantity, type
milk = ["Milk", 5.99, 2, "2% Milk"]   # Item name, price, quantity, type
apple = ["Apple", 1.27, 12, "Fuji"] # Item name, price, quantity, type

# Create the main grocery list that contains these items
grocery_list = [bread, apple, milk]
print("Grocery List:" , grocery_list)

# Accessing and printing specific item details using indexing
print("Item:", grocery_list[2][0]) # Accesses "Milk" title
print("Price:", grocery_list[2][1]) # Accesses price of a Milk, which is 5.99
print("Quantity:", grocery_list[2][2]) # Accesses quantity of Milk, which is 2
print("Type:", grocery_list[2][3]) # Accesses type of Milk, which is "2% Milk"

# Adding a new sublist item to the grocery list
onion = ["Onions", 1.30, 10, "Yellow"]
grocery_list.append(onion)

# Removing an item from the grocery list
grocery_list.remove(bread)

# Sorting the grocery list alphabetically
grocery_list.sort()
print("Updated Grocery List:", grocery_list)

The diagram below illustrates the nested list structure of grocery_list. Each item in the list, such as milk, apple, and bread, is itself a list containing a specific item details.

For instance, to access the price of milk, which is stored in the milk sublist, you use the syntax grocery_list[2][1]. Here, grocery_list[2] selects the milk sublist, and grocery_list[2][1] goes a step further to access the second element of that sublist — the price.

Task

Now it's your turn to update an inventory using lists. This challenge involves adjusting your grocery store's vegetable section. Start with a predefined list of vegetables, remove one, add two new ones, and sort the list alphabetically without introducing duplicates.

Create a variable named vegetables and assign it to the list containing "tomatoes", "potatoes", and "onions".
Remove "onions" from the list.
Add "carrots" to the end of the list if it has not already existed in the list.
Add "cucumbers" to the end of the list if it has not already existed in the list.
Sort the list alphabetically.

Task

Create a variable named vegetables and assign it to the list containing "tomatoes", "potatoes", and "onions".
Remove "onions" from the list.
Add "carrots" to the end of the list if it has not already existed in the list.
Add "cucumbers" to the end of the list if it has not already existed in the list.
Sort the list alphabetically.

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Section 4. Chapter 2

Nested Lists

Example Application

A customer in your grocery store has compiled a list of grocery items, where each item's details are stored in sublists under variable names.

We will help the customer access details from the milk sublist, add a new item, remove an existing item, and sort the entire grocery_list.

Let's start by creating a list first, and go step by step:


              12345678910111213141516171819202122232425
            
# Define individual grocery items as lists containing details
bread = ["Bread", 4.80, 3, "Gluten Free"] # Item name, price, quantity, type
milk = ["Milk", 5.99, 2, "2% Milk"]   # Item name, price, quantity, type
apple = ["Apple", 1.27, 12, "Fuji"] # Item name, price, quantity, type

# Create the main grocery list that contains these items
grocery_list = [bread, apple, milk]
print("Grocery List:" , grocery_list)

# Accessing and printing specific item details using indexing
print("Item:", grocery_list[2][0]) # Accesses "Milk" title
print("Price:", grocery_list[2][1]) # Accesses price of a Milk, which is 5.99
print("Quantity:", grocery_list[2][2]) # Accesses quantity of Milk, which is 2
print("Type:", grocery_list[2][3]) # Accesses type of Milk, which is "2% Milk"

# Adding a new sublist item to the grocery list
onion = ["Onions", 1.30, 10, "Yellow"]
grocery_list.append(onion)

# Removing an item from the grocery list
grocery_list.remove(bread)

# Sorting the grocery list alphabetically
grocery_list.sort()
print("Updated Grocery List:", grocery_list)

The diagram below illustrates the nested list structure of grocery_list. Each item in the list, such as milk, apple, and bread, is itself a list containing a specific item details.

Task

Create a variable named vegetables and assign it to the list containing "tomatoes", "potatoes", and "onions".
Remove "onions" from the list.
Add "carrots" to the end of the list if it has not already existed in the list.
Add "cucumbers" to the end of the list if it has not already existed in the list.
Sort the list alphabetically.

Task

Create a variable named vegetables and assign it to the list containing "tomatoes", "potatoes", and "onions".
Remove "onions" from the list.
Add "carrots" to the end of the list if it has not already existed in the list.
Add "cucumbers" to the end of the list if it has not already existed in the list.
Sort the list alphabetically.

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Section 4. Chapter 2

Nested Lists

Example Application

A customer in your grocery store has compiled a list of grocery items, where each item's details are stored in sublists under variable names.

We will help the customer access details from the milk sublist, add a new item, remove an existing item, and sort the entire grocery_list.

Let's start by creating a list first, and go step by step:


              12345678910111213141516171819202122232425
            
# Define individual grocery items as lists containing details
bread = ["Bread", 4.80, 3, "Gluten Free"] # Item name, price, quantity, type
milk = ["Milk", 5.99, 2, "2% Milk"]   # Item name, price, quantity, type
apple = ["Apple", 1.27, 12, "Fuji"] # Item name, price, quantity, type

# Create the main grocery list that contains these items
grocery_list = [bread, apple, milk]
print("Grocery List:" , grocery_list)

# Accessing and printing specific item details using indexing
print("Item:", grocery_list[2][0]) # Accesses "Milk" title
print("Price:", grocery_list[2][1]) # Accesses price of a Milk, which is 5.99
print("Quantity:", grocery_list[2][2]) # Accesses quantity of Milk, which is 2
print("Type:", grocery_list[2][3]) # Accesses type of Milk, which is "2% Milk"

# Adding a new sublist item to the grocery list
onion = ["Onions", 1.30, 10, "Yellow"]
grocery_list.append(onion)

# Removing an item from the grocery list
grocery_list.remove(bread)

# Sorting the grocery list alphabetically
grocery_list.sort()
print("Updated Grocery List:", grocery_list)

The diagram below illustrates the nested list structure of grocery_list. Each item in the list, such as milk, apple, and bread, is itself a list containing a specific item details.

Task

Create a variable named vegetables and assign it to the list containing "tomatoes", "potatoes", and "onions".
Remove "onions" from the list.
Add "carrots" to the end of the list if it has not already existed in the list.
Add "cucumbers" to the end of the list if it has not already existed in the list.
Sort the list alphabetically.

Task

Create a variable named vegetables and assign it to the list containing "tomatoes", "potatoes", and "onions".
Remove "onions" from the list.
Add "carrots" to the end of the list if it has not already existed in the list.
Add "cucumbers" to the end of the list if it has not already existed in the list.
Sort the list alphabetically.

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Example Application

A customer in your grocery store has compiled a list of grocery items, where each item's details are stored in sublists under variable names.

We will help the customer access details from the milk sublist, add a new item, remove an existing item, and sort the entire grocery_list.

Let's start by creating a list first, and go step by step:


              12345678910111213141516171819202122232425
            
# Define individual grocery items as lists containing details
bread = ["Bread", 4.80, 3, "Gluten Free"] # Item name, price, quantity, type
milk = ["Milk", 5.99, 2, "2% Milk"]   # Item name, price, quantity, type
apple = ["Apple", 1.27, 12, "Fuji"] # Item name, price, quantity, type

# Create the main grocery list that contains these items
grocery_list = [bread, apple, milk]
print("Grocery List:" , grocery_list)

# Accessing and printing specific item details using indexing
print("Item:", grocery_list[2][0]) # Accesses "Milk" title
print("Price:", grocery_list[2][1]) # Accesses price of a Milk, which is 5.99
print("Quantity:", grocery_list[2][2]) # Accesses quantity of Milk, which is 2
print("Type:", grocery_list[2][3]) # Accesses type of Milk, which is "2% Milk"

# Adding a new sublist item to the grocery list
onion = ["Onions", 1.30, 10, "Yellow"]
grocery_list.append(onion)

# Removing an item from the grocery list
grocery_list.remove(bread)

# Sorting the grocery list alphabetically
grocery_list.sort()
print("Updated Grocery List:", grocery_list)

The diagram below illustrates the nested list structure of grocery_list. Each item in the list, such as milk, apple, and bread, is itself a list containing a specific item details.

Task

Create a variable named vegetables and assign it to the list containing "tomatoes", "potatoes", and "onions".
Remove "onions" from the list.
Add "carrots" to the end of the list if it has not already existed in the list.
Add "cucumbers" to the end of the list if it has not already existed in the list.
Sort the list alphabetically.

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Section 4. Chapter 2

Switch to desktop for real-world practiceContinue from where you are using one of the options below