models.py 文件源码

def unique_for_country_code(self, country_code):
        shipping = self.filter(
            Q(country_code=country_code) |
            Q(country_code=ANY_COUNTRY))
        shipping = shipping.order_by('shipping_method_id')
        shipping = shipping.values_list('shipping_method_id', 'id', 'country_code')
        grouped_shipping = groupby(shipping, itemgetter(0))
        any_country = ANY_COUNTRY

        ids = []

        for shipping_method_id, method_values in grouped_shipping:
            method_values = list(method_values)
            # if there is any country choice and specific one remove any country choice
            if len(method_values) == 2:
                method = [val for val in method_values if val[2] != any_country][0]
            else:
                method = method_values[0]
            ids.append(method[1])
        return self.filter(id__in=ids)