Sometimes I need to slugify something within a django model or view file. Django already has this functionality written as a template filter, and you can reuse this outside of the templates. You can import slugify into your python code like so:

from django.template.defaultfilters import slugify

slugify(<value>)

Which then allows you to write something like:

class Custom(models.Model):
    name = models.CharField(max_length=100)
    slug = models.SlugField(blank=True)

    def save(self):
        self.slug = slugify(self.name)
        super(Custom, self).save()

However, if you need this type of functionality depending on your situation it might be easier to set this up using the django admin prepopulated_fields option.

# models.py
class Custom(models.Model):
    name = models.CharField(max_length=100)
    slug = models.SlugField()


# admin.py
class CustomAdmin(admin.ModelAdmin):
    prepopulated_fields = {'slug': ('name',)}

admin.site.register(Custom, CustomAdmin)

This will auto-populate the slug field while you type the name within the django admin.