Form validation (is_valid, cleaned_data) in Django - Mini Project: Build & Apply

Form validation (is_valid, cleaned_data)

📖 Scenario: You are building a simple Django web app where users can submit their name and age through a form.We want to check if the form data is valid and then access the cleaned data safely.

🎯 Goal: Create a Django form with fields for name and age. Then validate the form using is_valid() and access the cleaned data using cleaned_data.

📋 What You'll Learn

Create a Django form class called PersonForm with name (CharField) and age (IntegerField).

Create a dictionary called form_data with 'name': 'Alice' and 'age': 30.

Instantiate PersonForm with form_data.

Check if the form is valid using form.is_valid() and then access form.cleaned_data.

💡 Why This Matters

🌍 Real World

Forms are used in web apps to collect user input like registration, login, or surveys. Validating forms ensures data is correct before saving or processing.

💼 Career

Understanding Django form validation is essential for backend web developers working with user input and data integrity.

1

Create the form data dictionary

Create a dictionary called form_data with these exact entries: 'name': 'Alice' and 'age': 30.

Django

# Create the form_data dictionary with name and age
# Your code here

Need a hint?

Use curly braces {} to create a dictionary with keys 'name' and 'age'.

2

Create the PersonForm class

Create a Django form class called PersonForm that inherits from forms.Form. Add a name field as forms.CharField() and an age field as forms.IntegerField(). Import forms from django.

Django

form_data = {'name': 'Alice', 'age': 30}

# Import forms and create PersonForm class with name and age fields
# Your code here

Need a hint?

Use class PersonForm(forms.Form): and define fields inside the class.

3

Instantiate the form with data and validate

Create a variable called form and instantiate PersonForm with form_data. Then check if the form is valid using form.is_valid().

Django

from django import forms

form_data = {'name': 'Alice', 'age': 30}

class PersonForm(forms.Form):
    name = forms.CharField()
    age = forms.IntegerField()

# Instantiate PersonForm with form_data and check if valid
# Your code here

Need a hint?

Call PersonForm(form_data) to create the form instance, then call form.is_valid().

4

Access the cleaned data after validation

After confirming the form is valid, create a variable called cleaned and assign it the value of form.cleaned_data.

Django

from django import forms

form_data = {'name': 'Alice', 'age': 30}

class PersonForm(forms.Form):
    name = forms.CharField()
    age = forms.IntegerField()

form = PersonForm(form_data)
valid = form.is_valid()

# Assign form.cleaned_data to cleaned if form is valid
# Your code here

Need a hint?

Use an if statement to check valid before accessing cleaned_data.