Control structures (if, for) in Flask - Mini Project: Build & Apply

Flask Template Control Structures

📖 Scenario: You are building a simple Flask web page that shows a list of fruits and highlights which ones are favorites.

🎯 Goal: Create a Flask template that uses for loops and if statements to display fruits and mark favorites.

📋 What You'll Learn

Create a Python list called fruits with the exact values: 'Apple', 'Banana', 'Cherry', 'Date', 'Elderberry'

Create a Python list called favorite_fruits with the exact values: 'Banana', 'Date'

Use a Flask template with a for loop to go through fruits

Use an if statement inside the template to check if the fruit is in favorite_fruits and add '(Favorite)' next to it

💡 Why This Matters

🌍 Real World

Web developers often need to display lists of items with special highlights or conditions, like marking favorites or featured products.

💼 Career

Understanding how to use control structures in Flask templates is essential for backend web developers to create dynamic and user-friendly web pages.

1

Create the fruits list

Create a Python list called fruits with these exact values: 'Apple', 'Banana', 'Cherry', 'Date', 'Elderberry'.

Flask

# Create the fruits list
# Your code here

Need a hint?

Use square brackets [] to create a list and separate items with commas.

2

Create the favorite_fruits list

Create a Python list called favorite_fruits with these exact values: 'Banana', 'Date'.

Flask

fruits = ['Apple', 'Banana', 'Cherry', 'Date', 'Elderberry']
# Create the favorite_fruits list
# Your code here

Need a hint?

Use a list to store favorite fruits, just like the fruits list.

3

Add a for loop in the Flask template

In the Flask template, use a for loop with the variable fruit to iterate over fruits. Inside the loop, display each fruit inside a <li> tag.

Flask

fruits = ['Apple', 'Banana', 'Cherry', 'Date', 'Elderberry']
favorite_fruits = ['Banana', 'Date']

# Flask template starts here
"""

  {# Use a for loop to list fruits #}
  # Your code here

"""

Need a hint?

Use {% for fruit in fruits %} to start the loop and {% endfor %} to end it.

4

Add an if statement to mark favorites

Inside the for loop in the Flask template, add an if statement to check if fruit is in favorite_fruits. If yes, add the text (Favorite) after the fruit name inside the <li> tag.

Flask

fruits = ['Apple', 'Banana', 'Cherry', 'Date', 'Elderberry']
favorite_fruits = ['Banana', 'Date']

# Flask template starts here
"""

  {% for fruit in fruits %}
    {{ fruit }}
      {# Add if statement to check favorite fruits #}
      # Your code here
    
  {% endfor %}

"""

Need a hint?

Use {% if fruit in favorite_fruits %} to check and {% endif %} to close the condition.