Include for reusable fragments in Flask - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to include a reusable header fragment in a Flask Jinja2 template.

Flask

{% [1] 'header.html' %}

Drag options to blanks, or click blank then click option'

Ainclude

Bimport

Cextends

Dinsert

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'extends' instead of 'include' to insert fragments.

Trying to use 'import' which is for macros, not templates.

Using 'insert' which is not a valid Jinja2 tag.

In Flask Jinja2 templates, {% include 'filename' %} is used to insert reusable fragments like headers or footers.

2fill in blank

medium

Complete the code to include a footer fragment inside the main template.

Flask

<footer>{% [1] 'footer.html' %}</footer>

Drag options to blanks, or click blank then click option'

Aextends

Bimport

Cembed

Dinclude

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'extends' which is for template inheritance, not fragments.

Using 'import' which is for macros, not HTML fragments.

Using 'embed' which is not a valid Jinja2 tag.

The include tag inserts the content of footer.html inside the footer element.

3fill in blank

hard

Fix the error in the code to correctly include a navigation bar fragment.

Flask

{% [1] 'navbar.html' %}

Drag options to blanks, or click blank then click option'

Aimport

Bextends

Cinclude

Drequire

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'extends' which is for base templates, not fragments.

Using 'import' which is for macros, not HTML includes.

Using 'require' which is not a Jinja2 tag.

The correct tag to insert reusable HTML fragments is include. Using extends or others causes errors.

4fill in blank

hard

Fill both blanks to include a sidebar fragment and pass a variable to it.

Flask

{% [1] 'sidebar.html' with [2]=user %}

Drag options to blanks, or click blank then click option'

Ainclude

Bimport

Ccontext

Dextends

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'import' instead of 'include' for HTML fragments.

Passing variables incorrectly without 'with' keyword.

Using 'extends' which is for template inheritance.

Use include to insert the sidebar fragment and with to pass variables. The variable name follows 'with'.

5fill in blank

hard

Fill all three blanks to include a reusable card fragment with a title and content variables.

Flask

{% [1] 'card.html' with [2]=title, [3]=content %}

Drag options to blanks, or click blank then click option'

Ainclude

Btitle

Ccontent

Dimport

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'import' instead of 'include' for HTML fragments.

Swapping variable names or missing one variable.

Not using 'with' to pass variables.

Use include to insert the card fragment and pass title and content variables using with.

Practice

1. What is the main purpose of using {% include %} in Flask templates?

easy

A. To create new routes in Flask

B. To define variables in templates

C. To insert reusable HTML fragments into templates

D. To execute Python code inside templates

Solution

1. Step 1: Understand the role of {% include %}

   This tag is used to insert reusable HTML parts into templates to avoid repetition.

2. Step 2: Compare with other options

   Defining variables, creating routes, or executing Python code are not done with {% include %}.

3. Final Answer:

   To insert reusable HTML fragments into templates -> Option C

4. Quick Check:

   Reusable HTML insertion = A [OK]

Hint: Remember: include means insert reusable HTML [OK]

Common Mistakes:

• Confusing include with variable definition
• Thinking include creates routes
• Assuming include runs Python code

2. Which of the following is the correct syntax to include a reusable template named header.html inside another template?

easy

A. {% include 'header.html' %}

B. {% import 'header.html' %}

C. {{ include('header.html') }}

D. {% extend 'header.html' %}

Solution

1. Step 1: Recall the correct syntax for including templates

   The correct syntax uses {% include 'filename' %} with quotes around the filename.

2. Step 2: Eliminate incorrect options

   {% import %} is for macros, {{ include() }} is invalid, and {% extend %} is for template inheritance.

3. Final Answer:

   {% include 'header.html' %} -> Option A

4. Quick Check:

   Include syntax = {% include 'file' %} [OK]

Hint: Use {% include 'file.html' %} with quotes [OK]

Common Mistakes:

• Using {% import %} instead of {% include %}
• Trying to call include as a function {{ include() }}
• Confusing include with extend

3. Given the following templates, what will be rendered when base.html is rendered?

base.html:
<html>
  <body>
    {% include 'nav.html' %}
    <h1>Welcome</h1>
  </body>
</html>

nav.html:
<nav>Menu</nav>

medium

A. <nav>Menu</nav><h1>Welcome</h1>

B. <html><body><h1>Welcome</h1></body></html>

C. Error: nav.html not found

D. <html><body><nav>Menu</nav><h1>Welcome</h1></body></html>

Solution

1. Step 1: Understand how {% include %} works

   The {% include 'nav.html' %} inserts the content of nav.html exactly where the tag is placed.

2. Step 2: Combine the templates

   In base.html, the <nav>Menu</nav> from nav.html appears before the <h1>Welcome</h1> inside the body.

3. Final Answer:

   <html><body><nav>Menu</nav><h1>Welcome</h1></body></html> -> Option D

4. Quick Check:

   Include inserts nav.html content inline [OK]

Hint: Include inserts file content exactly where placed [OK]

Common Mistakes:

• Ignoring the included file content
• Expecting an error if file exists
• Thinking include replaces whole template

4. What is the error in this template snippet?

{% include header.html %}

medium

A. Filename should be a variable, not a string

B. Missing quotes around the filename

C. Incorrect tag name, should be import

D. Include tag cannot be used inside templates

Solution

1. Step 1: Check syntax for include tag

   The filename must be a string literal enclosed in quotes, like 'header.html'.

2. Step 2: Identify the error

   Here, header.html is unquoted, causing a syntax error.

3. Final Answer:

   Missing quotes around the filename -> Option B

4. Quick Check:

   Filename must be quoted in include [OK]

Hint: Always put quotes around filenames in include [OK]

Common Mistakes:

• Omitting quotes around filename
• Using import instead of include
• Thinking include is invalid in templates

5. You want to create a reusable footer for your Flask app. Which approach correctly uses {% include %} to add footer.html to multiple pages and ensures easy updates?

hard

A. Add {% include 'footer.html' %} in each page template where footer is needed

B. Copy footer HTML code into every page template manually

C. Use {% extend 'footer.html' %} in each page template

D. Write footer HTML inside the Flask route function

Solution

1. Step 1: Understand reusable fragments with include

   Using {% include 'footer.html' %} inserts the footer code wherever needed, keeping code DRY.

2. Step 2: Compare other options

   Copying code manually duplicates it, {% extend %} is for inheritance, and writing HTML in route mixes logic and presentation.

3. Final Answer:

   Add {% include 'footer.html' %} in each page template where footer is needed -> Option A

4. Quick Check:

   Include footer in templates for easy updates [OK]

Hint: Use include tag in templates to reuse footer [OK]

Common Mistakes:

• Copy-pasting footer code instead of including
• Using extend instead of include for fragments
• Mixing HTML in Python route code