Template variables with double braces in Django - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the rendered output of this Django template snippet?

Given the context {'user': {'name': 'Alice', 'age': 30}}, what will this template output?

{% raw %}Hello, {{ user.name }}! You are {{ user.age }} years old.{% endraw %}

A Hello, Alice! You are {{ user.age }} years old.

B Hello, {{ user.name }}! You are {{ user.age }} years old.

C Hello, user.name! You are user.age years old.

D Hello, Alice! You are 30 years old.

💡 Hint

Remember that double braces {{ }} output the value of the variable from the context.

The double braces {{ user.name }} and {{ user.age }} are replaced by the values from the context dictionary. So 'Alice' and '30' appear in the output.

📝 Syntax

intermediate

Which option correctly outputs the value of a variable in a Django template?

You want to display the value of the variable title in your Django template. Which syntax is correct?

A {{ title }}

B {% title %}

C {# title #}

D [[ title ]]

💡 Hint

Variables in Django templates are enclosed in double curly braces.

In Django templates, variables are displayed using double curly braces like {{ title }}. Other options are either template tags, comments, or invalid syntax.

🔧 Debug

advanced

What error occurs when using undefined variable in double braces?

Consider this template snippet:

{% raw %}Hello, {{ user.full_name }}!{% endraw %}

Given the context {'user': {}}, what happens when rendering?

A Outputs: Hello, ! (empty string for missing variable)

B TemplateSyntaxError: 'full_name' is not defined

C Raises KeyError at runtime

D Outputs: Hello, {{ user.full_name }}!

💡 Hint

Django templates silently ignore missing variables by default.

If a variable or attribute is missing in the context, Django outputs an empty string instead of raising an error.

🧠 Conceptual

advanced

How does Django template handle nested dictionary variables with double braces?

Given context {'product': {'name': 'Book', 'price': 12.99}}, what does this template output?

{% raw %}Product: {{ product.name }}, Price: ${{ product.price }}{% endraw %}

A Product: {{ product.name }}, Price: ${{ product.price }}

B Product: Book, Price: $12.99

C Product: Book, Price: ${{ price }}

D Product: product.name, Price: $product.price

💡 Hint

Double braces access nested dictionary keys using dot notation.

Django templates allow accessing nested dictionary keys with dot notation inside double braces, so the values are replaced correctly.

❓ state_output

expert

What is the output when using a filter with double braces in Django template?

Given context {'name': 'alice'}, what is the output of this template?

{% raw %}Hello, {{ name|capfirst }}!{% endraw %}

A Hello, ALICE!

B Hello, alice!

C Hello, Alice!

D Hello, {{ name|capfirst }}!

💡 Hint

The capfirst filter capitalizes the first letter of the string.

The capfirst filter changes the first character to uppercase, so 'alice' becomes 'Alice'.

Practice

1. What does the double braces syntax {{ variable }} do in a Django template?

easy

A. It displays the value of the variable passed from the view.

B. It runs a Python function inside the template.

C. It comments out the variable so it is not shown.

D. It creates a new variable inside the template.

Solution

1. Step 1: Understand Django template variable syntax

   Double braces {{ }} are used to show variables passed from the view inside the HTML template.

2. Step 2: Identify the purpose of {{ variable }}

   It outputs the value of the variable, making it visible in the rendered page.

3. Final Answer:

   It displays the value of the variable passed from the view. -> Option A

4. Quick Check:

   Double braces show variable value = A [OK]

Hint: Double braces always output variable values in templates [OK]

Common Mistakes:

• Thinking {{ }} runs Python code
• Confusing {{ }} with comments
• Assuming {{ }} creates variables

2. Which of the following is the correct way to display a variable named user_name in a Django template?

easy

A. {% user_name %}

B. <% user_name %>

C. {{ user_name }}

D. [[ user_name ]]

Solution

1. Step 1: Recall Django template variable syntax

   Variables are displayed using double braces {{ variable_name }} in Django templates.

2. Step 2: Match the correct syntax for user_name

   The correct syntax is {{ user_name }} to show the variable's value.

3. Final Answer:

   {{ user_name }} -> Option C

4. Quick Check:

   Use double braces for variables = B [OK]

Hint: Remember: variables use {{ }} not {% %} [OK]

Common Mistakes:

• Using {% %} which is for template tags
• Using <% %> which is not Django syntax
• Using [[ ]] which is not valid

3. Given the view passes {'count': 5} to the template, what will be rendered by this template code?

<p>Total items: {{ count }}</p>

medium

A. Total items: count

B. Total items: 5

C. Total items: {{ count }}

D. Total items:

Solution

1. Step 1: Understand variable substitution in template

   The variable 'count' with value 5 is passed from the view to the template.

2. Step 2: Replace {{ count }} with its value

   The template engine replaces {{ count }} with 5 in the rendered HTML.

3. Final Answer:

   <p>Total items: 5</p> -> Option B

4. Quick Check:

   Variable replaced by value = D [OK]

Hint: Variables inside {{ }} show their values, not names [OK]

Common Mistakes:

• Expecting the variable name to show instead of value
• Thinking {{ count }} stays as is in output
• Leaving the variable empty if not recognized

4. What is wrong with this Django template code if the view passes {'user': {'name': 'Anna'}}?

<p>User: {{ user.name }}</p>

medium

A. The variable name must be capitalized as {{ User.Name }}.

B. Django templates cannot access dictionary keys with dot notation.

C. The variable should be accessed as {{ user['name'] }} instead.

D. The syntax is correct; it will display 'User: Anna'.

Solution

1. Step 1: Check how Django templates access dictionary keys

   Django templates allow accessing dictionary keys using dot notation like {{ user.name }}.

2. Step 2: Confirm the output

   Since user is a dictionary with key 'name', {{ user.name }} will correctly display 'Anna'.

3. Final Answer:

   The syntax is correct; it will display 'User: Anna'. -> Option D

4. Quick Check:

   Dot notation works for dict keys = A [OK]

Hint: Use dot notation for dict keys in templates [OK]

Common Mistakes:

• Trying to use bracket notation in templates
• Assuming dot notation only works for objects
• Capitalizing variable names incorrectly

5. You want to display a user's full name in a template. The view passes {'user': {'first_name': 'John', 'last_name': 'Doe'}}. Which template code correctly shows "John Doe" using double braces?

hard

A. {{ user.first_name }} {{ user.last_name }}

B. {{ user['first_name'] + ' ' + user['last_name'] }}

C. {{ user.first_name | add:' ' | add:user.last_name }}

D. {% user.first_name %} {% user.last_name %}

Solution

1. Step 1: Understand how to access dictionary keys in templates

   Use dot notation {{ user.first_name }} and {{ user.last_name }} to get values.

2. Step 2: Combine variables with a space in between

   Write both variables separated by a space in the template to display full name.

3. Step 3: Check other options for correctness

   {{ user['first_name'] + ' ' + user['last_name'] }} uses invalid syntax for concatenation in templates; {{ user.first_name | add:' ' | add:user.last_name }} uses a wrong filter; {% user.first_name %} {% user.last_name %} uses wrong tag syntax.

4. Final Answer:

   {{ user.first_name }} {{ user.last_name }} -> Option A

5. Quick Check:

   Use dot notation and space for concatenation = C [OK]

Hint: Use {{ var1 }} {{ var2 }} to join values with space [OK]

Common Mistakes:

• Trying to concatenate strings inside {{ }} directly
• Using {% %} tags for variables
• Using filters incorrectly for string join