CODEWITHSUNDEEP
jsondjangodjango-modelsdjango-views
Rookie_123
Rookie_123

Reputation: 2017

__str__ returned non-string (type list)

I am having a django app in which I am storing the json variable.I have stored the json variable through admin and I am trying to print it in shell.My main aim is to pass this variable to a webpage with ajax method.But first when I was trying to print it in shell I get this error

__str__ returned non-string (type list)

My models.py is of this form

from django.db import models
from django.utils import timezone
from jsonfield import JSONField


# Create your models here.


class newgrid(models.Model):
    data = JSONField()
    def __str__(self):
        return self.data

My JSON variable is of this form 

[{"col":1,"row":1,"size_x":1,"size_y":1},{"col":2,"row":1,"size_x":1,"size_y":1},{"col":3,"row":1,"size_x":1,"size_y":1},{"col":4,"row":1,"size_x":1,"size_y":1},{"col":1,"row":2,"size_x":1,"size_y":1},{"col":2,"row":2,"size_x":1,"size_y":1},{"col":3,"row":2,"size_x":1,"size_y":1},{"col":4,"row":2,"size_x":1,"size_y":1},{"col":1,"row":3,"size_x":1,"size_y":1},{"col":2,"row":3,"size_x":1,"size_y":1},{"col":3,"row":3,"size_x":1,"size_y":1},{"col":4,"row":3,"size_x":1,"size_y":1},{"col":5,"row":1,"size_x":1,"size_y":1}]

In shell I ran following commands 

from testforweb.models import newgrid
newgrid.objects.all()

It initially returned this 

<QuerySet [<newgrid: newgrid object (1)>]>

But then I added 

 def __str__(self):
        return self.data

Just to see the actual JSON variable.But I am getting the error How to see the actual JSON variable which I inserted through admin coz I need to send it to webpage as it is

Edit 1

My updated models.py
from django.db import models
from django.utils import timezone
from jsonfield import JSONField
import simplejson as json

# Create your models here.


    class newgrid(models.Model):
        data = JSONField()
        def __str__(self):
            json.dumps(self.data)

Upvotes: 1

Views: 1287

Answers (3)

SuReSh
SuReSh

Reputation: 1511

Use

   def __str__(self):
        return '%s' % (self.data)

Instead of 

   def __str__(self):
        return json.dumps(self.data)

Upvotes: 1

albar
albar

Reputation: 3100

The __str__ function must return a string:

    def __str__(self):
        return json.dumps(self.data)

Upvotes: 3

Danny Staple
Danny Staple

Reputation: 7332

The JSON field will actually decode the JSON into native python types (lists and dictionaries).

The __str___ method is always expected to return a string. If you want a string representation of the json, you should use json.dumps(self.data) or similar to serialise the data field as the return value of __str__.

Upvotes: 1

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