Setting the selected value on a Django forms.ChoiceField

Try setting the initial value when you instantiate the form:

form = MyForm(initial={'max_number': '3'})

This doesn't touch on the immediate question at hand, but this Q/A comes up for searches related to trying to assign the selected value to a ChoiceField.

If you have already called super().__init__ in your Form class, you should update the form.initial dictionary, not the field.initial property. If you study form.initial (e.g. print self.initial after the call to super().__init__), it will contain values for all the fields. Having a value of None in that dict will override the field.initial value.

e.g.

class MyForm(forms.Form):
    def __init__(self, *args, **kwargs):
        super(MyForm, self).__init__(*args, **kwargs)
        # assign a (computed, I assume) default value to the choice field
        self.initial['choices_field_name'] = 'default value'
        # you should NOT do this:
        self.fields['choices_field_name'].initial = 'default value'