django - List field in model?

Question

In my model, I want a field that has a list of triplets. e.g. [[1, 3, 4], [4, 2, 6], [8, 12, 3], [3, 3, 9]]. Is there a field that can store this data in the database?

Answer 1

You can convert it into string by using JSON and store it as string.

For example,

In [3]: json.dumps([[1, 3, 4], [4, 2, 6], [8, 12, 3], [3, 3, 9]])

Out[3]: '[[1, 3, 4], [4, 2, 6], [8, 12, 3], [3, 3, 9]]'

You can add a method into your class to convert it automatically for you.

import json


class Foobar(models.Model):
    foo = models.CharField(max_length=200)

    def set_foo(self, x):
        self.foo = json.dumps(x)

    def get_foo(self):
        return json.loads(self.foo)

If you're using Django 1.9 or above, and you use postgresql, there is a new class called JSONField, you should use it instead. Here is a link to it

There is a good talk about PostgreSQL JSONs and Arrays on youtube. Watch it, it has very good information.