I’m trying to add a field to a Django model that will represent a

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Asked: May 18, 20262026-05-18T00:03:06+00:00 2026-05-18T00:03:06+00:00

I’m trying to add a field to a Django model that will represent a

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I’m trying to add a field to a Django model that will represent a list of email addresses. I would like a user to enter a comma separated list of addresses into a form in the admin, which my app will then parse to send out a series of emails.

My current implementation covers the basic idea, but has a significant limitation. In the admin, if I enter a string like foo@example.com, bar@example.com, then it correctly writes this to the database as [u'foo@example.com', u'bar@example.com']. But the admin displays this serialized value instead of the humanized string. More importantly, if I edit and save the record, without making any changes, the same conversion changes [u'foo@example.com', u'bar@example.com'] to [u"[u'foo@example.com'", u"u'bar@example.com']"].

How do I convert the python list representation back to a string for use in the admin? Is that the purpose of the value_to_string method or do I need to make the conversion someplace else?

My current custom model field is as follows:

class EmailListField(models.TextField):
    __metaclass__ = models.SubfieldBase

    def to_python(self, value):
        if not value:
            return
        if isinstance(value, list):
            return value
        return [address.strip() for address in value.split(',')]

    def get_db_prep_value(self, value):
        if not value:
            return
        return ','.join(unicode(s) for s in value)

    def value_to_string(self, obj):
        value = self._get_val_from_obj(obj)
        return self.get_db_prep_value(value)

This is based on the SeparatedValuesField described here: http://www.davidcramer.net/code/181/custom-fields-in-django.html.