Field.required
By default, each Field
class assumes the value is required, so if you pass an empty value – either None
or the empty string (""
) – then clean()
will raise a ValidationError
exception:
>>> from django import forms >>> f = forms.CharField() >>> f.clean('foo') 'foo' >>> f.clean('') Traceback (most recent call last): ... ValidationError: ['This field is required.'] >>> f.clean(None) Traceback (most recent call last): ... ValidationError: ['This field is required.'] >>> f.clean(' ') ' ' >>> f.clean(0) '0' >>> f.clean(True) 'True' >>> f.clean(False) 'False'
To specify that a field is not required, pass required=False
to the Field
constructor:
>>> f = forms.CharField(required=False) >>> f.clean('foo') 'foo' >>> f.clean('') '' >>> f.clean(None) '' >>> f.clean(0) '0' >>> f.clean(True) 'True' >>> f.clean(False) 'False'
If a Field
has required=False
and you pass clean()
an empty value, then clean()
will return a normalized empty value rather than raising ValidationError
. For CharField
, this will be a Unicode empty string. For other Field
classes, it might be None
. (This varies from field to field.)
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