Django set model value, using another value of the same model

Question

I am creating a board game, and I want to set value job_exp using an age value, I tried to use redefined save method, but it changes value after each save,so I try to create method, but I got:

TypeError: unsupported operand type(s) for -: 'IntegerField' and 'int'

Here is models:

class Character(models.Model):
    def set_job_exp(age):
        return randint(0, age - 18)

    age = models.IntegerField("Age",default=randint(18, 100))
    job_exp = models.IntegerField('Job exp',blank=True,default=set_job_exp(age)

How to convert IntegerField to int or do you have any ideas how to solve it?

Answer 1

You can do it by redefining.save() method for cases like this. Here you can check if an instance does not have a pk value then it is a new instance and about to be created.

def save(self, *args, **kwargs):
    if not self.pk:
        self.job_exp = randint(0, self.age - 18)
    super().save(*args, **kwargs)