Question

I am newbie at Django. I have model with a custom method. In view I am
retrieving a single object.

Here is my code — My model

class Problem(models.Model): 
    problem = models.CharField(max_length=100) 
    solution=models.CharField(max_length=500) 
    def __unicode__(self): 
        return self.problem 
   def retrieve_rankdata(self): 
                return self.problem.split()[0].split('/') 

in view I am doing this

def show(request): 
       problem = Problem.objects.all()[0] 
        t1=problem.retrieve_rankdata() 

But, I am getting this error
‘Problem’ object has no attribute ‘retrieve_rankdata’

What am I doing wrong?

Answer 1

It’s a bit hard to tell, but the problem could be with your indentation. The indentation in the code you’ve pasted is inconsistent, so it wouldn’t work properly anyway – I suspect in your actual code, def retrieve_rankdata is a couple more spaces to the left.

Don’t forget that Python uses indentation to tell whether or not an attribute or a method is part of a class. So if your def retrieve_rankdata line is not actually indented at the same level as the def __unicode__ one, it won’t be considered part of the Problem class.