is_valid and cleaned_data
Validate input and read clean values.
is_valid and cleaned_data is a free Django Academy lesson on CoddyKit. This is lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Django Academy learning path, and your progress syncs across the web and the CoddyKit app. The Django Academy course includes 4 lessons in total.
Bind Data First
To validate, create a bound form by passing the submitted data into it. Only bound forms can be validated.
form = ContactForm(request.POST)Call is_valid()
is_valid() runs every field validation and returns True only if all of them pass. It triggers the whole cleaning process.
if form.is_valid():
handle(form)cleaned_data Appears
After is_valid() returns True, Django fills cleaned_data, a dict of validated, type-converted values ready to use.
name = form.cleaned_data["name"]Values Are Converted
Cleaning converts types too. An IntegerField gives you a real int, and a DateField gives you a Python date, not raw strings.
age = form.cleaned_data["age"] # intErrors Collect Automatically
If validation fails, the messages land in form.errors, keyed by field name so you can show each problem clearly.
if not form.is_valid():
print(form.errors)Field-Level clean Methods
Add a method named clean_field to validate one field and return its cleaned value. Raise ValidationError to reject it.
def clean_name(self):
name = self.cleaned_data["name"]
return name.strip()Raise ValidationError
Inside a clean method, raise ValidationError with a message to reject the value and attach an error to that field.
if "@" not in email:
raise forms.ValidationError("Bad email")Form-Wide clean()
Override clean() to validate fields against each other, like confirming two passwords match across the whole form.
def clean(self):
cleaned = super().clean()
return cleanedCross-Field Checks
In clean() you can read several cleaned_data keys and raise an error when their combination is invalid.
if start > end:
raise forms.ValidationError("Bad range")The Cleaning Order
Django runs field cleaning first, then your form-wide clean(). So clean() can safely rely on already-validated field values.
Use cleaned_data Safely
Always read input from cleaned_data, never from request.POST. Only cleaned_data holds validated, converted, trusted values.
email = form.cleaned_data["email"]Quick Check
Test your grip on validation.
Recap
Bind data, call is_valid(), then read trusted values from cleaned_data. Use clean methods to add your own rules. ✅
Frequently Asked Questions
Is the “is_valid and cleaned_data” lesson free?
Yes — the full text of “is_valid and cleaned_data” is free to read here on the web. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Django Academy course, upgrade to CoddyKit PRO. The Django Academy course includes 4 lessons in total.
What will I learn in “is_valid and cleaned_data”?
Validate input and read clean values. You practise Django Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Django Academy?
No prior experience is required. Django Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 2 of 4.
How long does the “is_valid and cleaned_data” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Django Academy lesson?
Yes. Every Django Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Defining a forms.Form
- is_valid and cleaned_data
- Rendering Forms in Templates
- CSRF Protection and the POST Flow