Creating a class in python using a string as the class name

Question

I have been looking for this for quite sometime and also looked at previously asked questions like:

how to dynamically create an instance of a class in python?

Does python have an equivalent to Java Class.forName()?

Can you use a string to instantiate a class in python?

And also many more, in some of them they are importing the class or using the name of the class somehow in definition.

Edit:

I need to take a list as input and create classes with strings in the list as their name.

store_list = {'store1', 'storeabc', 'store234'}

Now i can do,

store1 = type(store_list[0], (models.Model,), attrs)
storeabc = type(store_list[1], (models.Model,), attrs)
store234 = type(store_list[2], (models.Model), attrs)

But i still have to use the names of the class in some way in the code, i have no way of knowing what the list will be, and i want the classes to be created with name taken from the list.

Do you want to create an object from a class or do you want to create the class itself dynamically? If the later have you looked at this question? — syntonym
– syntonym, Commented Jul 5, 2016 at 9:38
We need minimal reproducible example - sample input and expected output. — Łukasz Rogalski
– Łukasz Rogalski, Commented Jul 5, 2016 at 9:39
“But i still have to use the names of the class in some way in the code” – for example..? — poke
– poke, Commented Jul 5, 2016 at 10:12
How can you "use the names of the class ... in the code" when you have "no way of knowing what the names will be" ? — donkopotamus
– donkopotamus, Commented Jul 5, 2016 at 10:17

davidedb · Accepted Answer · 2016-07-10 19:57:56Z

2

You could store the classes you're dynamically creating into a dictionary, mapping class names to classes. This way you can use such a dictionary to access your classes by name later in your code, e.g. to create instances. For example:

store_list = {'store1', 'storeabc', 'store234'}
name2class = {}
for name in store_list:
    name2class[name] = type(name, (models.Model,), attrs)
. . .
my_instance = name2class[name](...)

answered Jul 10, 2016 at 19:57

davidedb

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