Interview question

What is the Django Template Language (DTL) and how does it differ from plain Python? Django Template Language (DTL) क्या है और plain Python से कैसे अलग है?

Answer

DTL is a restricted, designer-friendly templating syntax embedded in HTML files, intentionally limited so templates stay simple and separated from complex business logic.

# book_list.html
<h1>Books</h1>
<ul>
{% for book in books %}
    <li>{{ book.title }} - ${{ book.price }}</li>
{% empty %}
    <li>No books available</li>
{% endfor %}
</ul>

{% if user.is_authenticated %}
    <p>Welcome, {{ user.username }}!</p>
{% else %}
    <p>Please log in</p>
{% endif %}

DTL restriction	Why it exists
No arbitrary Python expressions ({{ x + y }} works only for simple cases via filters)	Keeps templates safe for non-programmers (designers) to edit
No function calls with arguments directly	Prevents complex logic from leaking into presentation layer
Dot notation (.) accesses attributes, dict keys, AND method calls uniformly	Simplifies syntax - {{ obj.attr }} works whether attr is a field, method, or dict key

# {{ book.title }} tries, in order:
# 1. book['title'] (dictionary lookup)
# 2. book.title (attribute lookup)
# 3. book.title() (method call, if title is callable)
# 4. book[0] (numeric index, if title is a number)

# Rendering a template from a view
from django.shortcuts import render
def book_list(request):
    books = Book.objects.all()
    return render(request, 'book_list.html', {'books': books, 'page_title': 'All Books'})

DTL एक restricted, designer-friendly templating syntax है जो HTML files में embedded होता है, जानबूझकर limited है ताकि templates simple रहें और complex business logic से अलग हों।

# book_list.html
<h1>Books</h1>
<ul>
{% for book in books %}
    <li>{{ book.title }} - ${{ book.price }}</li>
{% empty %}
    <li>कोई books उपलब्ध नहीं</li>
{% endfor %}
</ul>

{% if user.is_authenticated %}
    <p>Welcome, {{ user.username }}!</p>
{% else %}
    <p>कृपया login करें</p>
{% endif %}

DTL restriction	क्यों है
Arbitrary Python expressions नहीं	Templates को designers के लिए safe रखता है
Function calls सीधे arguments के साथ नहीं	Complex logic presentation layer में नहीं आती
Dot notation (.) attributes, dict keys, method calls सबके लिए	Syntax simplify करता है

# {{ book.title }} इस order में try करता है:
# 1. book['title']
# 2. book.title
# 3. book.title() (callable हो तो)
# 4. book[0]

from django.shortcuts import render
def book_list(request):
    books = Book.objects.all()
    return render(request, 'book_list.html', {'books': books, 'page_title': 'All Books'})

Was this answer clear?

Subjects

Related questions