Commit 01b0eb50 authored by Alex Gaynor's avatar Alex Gaynor
Browse files

Make ``Formset.__getitem__`` O(1), rather than O(n). If you override... 

Make ``Formset.__getitem__`` O(1), rather than O(n).  If you override ``__iter__`` you now need to also override ``__getitem__`` for consistant behavior.  Thanks to Carl and Russ for the review.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16770 bcc190cf-cafb-0310-a4f2-bffc1f526a37
parent 5f287f75

django/forms/formsets.py

+1 −1
Original line number Diff line number Diff line
@@ -55,7 +55,7 @@ class BaseFormSet(StrAndUnicode): 


    def __getitem__(self, index):

        """Returns the form at the given index, based on the rendering order"""

        return list(self)[index]

        return self.forms[index]



    def __len__(self):

        return len(self.forms)

docs/topics/forms/formsets.txt

+4 −0
Original line number Diff line number Diff line
@@ -49,6 +49,10 @@ they were created. The default formset iterator also renders the forms 
in this order, but you can change this order by providing an alternate

implementation for the :meth:`__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.



Using initial data with a formset

---------------------------------

tests/regressiontests/forms/tests/formsets.py

+11 −9
Original line number Diff line number Diff line
@@ -793,8 +793,10 @@ class FormsFormsetTestCase(TestCase): 
        # Formets can override the default iteration order

        class BaseReverseFormSet(BaseFormSet):

            def __iter__(self):

                for form in reversed(self.forms):

                    yield form

                return reversed(self.forms)



            def __getitem__(self, idx):

                return super(BaseReverseFormSet, self).__getitem__(len(self) - idx - 1)



        ReverseChoiceFormset = formset_factory(Choice, BaseReverseFormSet, extra=3)

        reverse_formset = ReverseChoiceFormset()