forms.formsets.BaseFormSet

class BaseFormSet [source]

A formset is a layer of abstraction to work with multiple forms on the same page. It can be best compared to a data grid. Let’s say you have the following form:

>>> from django import forms
>>> class ArticleForm(forms.Form):
...     title = forms.CharField()
...     pub_date = forms.DateField()

You might want to allow the user to create several articles at once. To create a formset out of an ArticleForm you would do:

>>> from django.forms import formset_factory
>>> ArticleFormSet = formset_factory(ArticleForm)

You now have created a formset named ArticleFormSet. The formset gives you the ability to iterate over the forms in the formset and display them as you would with a regular form:

>>> formset = ArticleFormSet()
>>> for form in formset:
...     print(form.as_table())
<tr><th><label for="id_form-0-title">Title:</label></th><td><input type="text" name="form-0-title" id="id_form-0-title" /></td></tr>
<tr><th><label for="id_form-0-pub_date">Pub date:</label></th><td><input type="text" name="form-0-pub_date" id="id_form-0-pub_date" /></td></tr>

As you can see it only displayed one empty form. The number of empty forms that is displayed is controlled by the extra parameter. By default, formset_factory() defines one extra form; the following example will display two blank forms:

>>> ArticleFormSet = formset_factory(ArticleForm, extra=2)

Iterating over the formset will render the forms in the order they were created. You can change this order by providing an alternate implementation for the __iter__() method.

Formsets can also be indexed into, which returns the corresponding form. If you override __iter__, you will need to also override __getitem__ to have matching behavior.