Django / Python update field values ​​(during model save)

Question

I try to use some fields in my django models when they are saved. Looking at this question that this answer was:

class Blog(models.Model): name = models.CharField(max_length=100) def save(self): self.name = self.name.title() super(Blog, self).save() 

This works great, however in each save it requires some extra typing if I want to repeat this several times. Therefore, I would like to create a function that takes fields as input and saves them as uppercase during the save step. So I wrote this to check it out:

 def save(self): for field in [self.first_name, self.last_name]: field = field.title() super(Artist,self).save() 

However, if I had thought about this earlier, I would have realized that this simply overwrites the field variable. I want to cycle through a list of variables to change them. I know that some functions change the value in place without using = . How do they do it? Can i achieve this?

Or is there some simpler way to do what I'm doing? Am I mistaken?

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SOLUTION: From the first answer, I made a function:

 def cap(self, *args): for field in args: value = getattr(self, field) setattr(self, field, value.title()) 

and in my models:

 def save(self): cap(self,'first_name', 'last_name') super(Artist,self).save() 

Answer 1

To achieve this, you can use setattr (self, my_field_name, value).

 for field in ['first_name', 'last_name']: value = getattr(self, field) setattr(self, field, value.title()) 

You cannot change the value in place, since strings are immutable in Python.