URL parameters with angle brackets in Django

Introduction

URL parameters with angle brackets let you capture parts of a web address as variables. This helps your website show different content based on the URL.

You want to show a user profile page based on the user ID in the URL.

You need to display a blog post using its unique slug from the URL.

You want to filter products by category name passed in the URL.

You want to pass a date or number in the URL to show specific data.

You want to create clean, readable URLs that include dynamic parts.

Syntax

Django

path('route/<converter:name>/', view_function, name='route_name')

The angle brackets <> capture URL parts as variables.

The converter defines the type of variable (like int, str, slug).

Examples

This captures an integer from the URL as user_id.

Django

path('user/<int:user_id>/', views.user_detail, name='user_detail')

This captures a slug (letters, numbers, hyphens) as post_slug.

Django

path('post/<slug:post_slug>/', views.post_detail, name='post_detail')

This captures any string as category_name.

Django

path('category/<str:category_name>/', views.category_view, name='category_view')

Sample Program

This example shows a URL pattern that captures a username from the URL and passes it to the greet_user view. The view then returns a greeting message using that username.

Django

from django.urls import path
from django.http import HttpResponse

# View function that uses URL parameter

def greet_user(request, username):
    return HttpResponse(f"Hello, {username}!")

# URL patterns list
urlpatterns = [
    path('hello/<str:username>/', greet_user, name='greet_user'),
]

Important Notes

Use the correct converter to match the expected data type.

If you omit the converter, Django treats the parameter as a string by default.

Angle brackets must be used exactly as shown to capture parameters.

Summary

Angle brackets <> in Django URLs capture parts of the URL as variables.

Converters like int, str, and slug define the variable type.

This helps create dynamic, readable URLs that pass data to views.

Practice

1. What does the angle bracket syntax <int:id> in a Django URL pattern do?

easy

A. Creates a static URL segment named 'int:id'.

B. Specifies a query parameter instead of a URL segment.

C. Defines a string variable named 'id' without type conversion.

D. Captures a part of the URL as an integer variable named 'id'.

Solution

1. Step 1: Understand angle brackets in Django URLs

   Angle brackets capture parts of the URL as variables to pass to views.

2. Step 2: Recognize the converter and variable name

   The syntax <int:id> captures an integer named 'id'.

3. Final Answer:

   Captures a part of the URL as an integer variable named 'id'. -> Option D

4. Quick Check:

   URL parameter with <int:id> = integer variable capture [OK]

Hint: Angle brackets capture URL parts as typed variables [OK]

Common Mistakes:

• Thinking it creates a static URL segment
• Confusing query parameters with URL parameters
• Ignoring the type converter like int or str

2. Which of the following is the correct syntax to capture a slug parameter named 'post_slug' in a Django URL pattern?

easy

A. path('post/<str:post_slug>/', views.post_detail)

B. path('post/<slug:post_slug>/', views.post_detail)

C. path('post/<post_slug:slug>/', views.post_detail)

D. path('post/<slug>post_slug/', views.post_detail)

Solution

1. Step 1: Identify correct converter and variable order

   The correct syntax is <converter:variable_name>, so <slug:post_slug> is correct.

2. Step 2: Check the full path syntax

   path('post/<slug:post_slug>/', views.post_detail) uses path('post/<slug:post_slug>/', views.post_detail), which is valid Django syntax.

3. Final Answer:

   path('post/<slug:post_slug>/', views.post_detail) -> Option B

4. Quick Check:

   Converter before variable name = path('post/<slug:post_slug>/', views.post_detail) [OK]

Hint: Use <converter:variable> format for URL parameters [OK]

Common Mistakes:

• Swapping converter and variable name
• Missing colon between converter and variable
• Using invalid syntax like <slug>post_slug

3. Given this URL pattern: path('user/<int:user_id>/', views.profile), what will user_id be if the URL is /user/42/?

medium

A. A slug '42'

B. The string '42'

C. The integer 42

D. A syntax error occurs

Solution

1. Step 1: Understand the int converter effect

   The <int:user_id> converter converts the URL segment to an integer.

2. Step 2: Apply to the URL segment '42'

   The string '42' from the URL is converted to the integer 42 before passing to the view.

3. Final Answer:

   The integer 42 -> Option C

4. Quick Check:

   int converter converts URL part to integer [OK]

Hint: int converter makes URL part an integer, not string [OK]

Common Mistakes:

• Assuming the parameter is a string
• Confusing slug with int converter
• Expecting a syntax error for valid syntax

4. Identify the error in this Django URL pattern: path('article/<int:id>', views.detail)

medium

A. Missing closing angle bracket '>' after 'id'.

B. Using 'int' converter instead of 'str'.

C. View function 'detail' is not imported.

D. URL pattern should not use angle brackets.

Solution

1. Step 1: Check angle bracket syntax

   The pattern uses <int:id> without the closing '>' character, which is invalid syntax.

2. Step 2: Confirm correct syntax

   The correct syntax requires both opening and closing angle brackets: <int:id>.

3. Final Answer:

   Missing closing angle bracket '>' after 'id'. -> Option A

4. Quick Check:

   Angle brackets must be complete <int:id> [OK]

Hint: Always close angle brackets in URL parameters [OK]

Common Mistakes:

• Forgetting the closing '>'
• Confusing converter types
• Assuming view import errors cause syntax issues

5. You want to create a URL pattern that captures a username (letters, numbers, underscores) and a post ID (integer). Which of these is the best Django URL pattern?

hard

A. path('profile/<slug:username>/post/<int:post_id>/', views.post_view)

B. path('profile/<str:username>/post/<int:post_id>/', views.post_view)

C. path('profile/<int:username>/post/<int:post_id>/', views.post_view)

D. path('profile/<username>/post/<post_id>/', views.post_view)

Solution

1. Step 1: Choose correct converter for username

   Usernames usually contain letters, numbers, underscores, so 'slug' converter fits best.

2. Step 2: Confirm integer converter for post ID

   Post ID should be an integer, so <int:post_id> is correct.

3. Step 3: Evaluate options

   path('profile/<slug:username>/post/<int:post_id>/', views.post_view) uses <slug:username> and <int:post_id>, matching requirements perfectly.

4. Final Answer:

   path('profile/<slug:username>/post/<int:post_id>/', views.post_view) -> Option A

5. Quick Check:

   Slug for username + int for post ID = path('profile/<slug:username>/post/<int:post_id>/', views.post_view) [OK]

Hint: Use slug for usernames, int for numeric IDs in URLs [OK]

Common Mistakes:

• Using str converter which allows spaces
• Using int converter for username
• Omitting converters causing string default