How to generate Pydantic model for multiple different objects

How to Generate Pydantic Model for Multiple Different Objects

In this technical blog post, we will explore how to generate a Pydantic model for multiple different objects.

Problem Statement:

You have multiple different types of objects that you want to represent using Pydantic models. Each type of object has its own set of attributes. You want to be able to create a single Pydantic model that can represent all of the different types of objects.

Solution:

There are a few different ways to approach this problem. One common solution is to use a Union type. A Union type allows you to specify multiple different types that a single model attribute can accept. For example, you could create a Variable model that has a vtype attribute of type VarType, a guess attribute of type Union[int, float, str], and a min and max attribute of type Optional[Union[int, float]].

from enum import Enum
from pydantic import BaseModel, Union, Optional

class VarType(Enum):
    int = "int"
    cont = "cont"
    cat = "cat"

class Variable(BaseModel):
    vtype: VarType
    guess: Union[int, float, str]
    min: Optional[Union[int, float]] = None
    max: Optional[Union[int, float]] = None

This model would allow you to represent three different types of variables: integer variables, continuous variables, and categorical variables. You could then create a list or dictionary of Variable objects to represent a collection of different variables.

Another Solution:

Another solution is to use a custom root type. A custom root type allows you to define a Pydantic model that does not have a predefined set of attributes. This gives you more flexibility in terms of the structure of your model. For example, you could create a custom root type called Item that has a __root__ attribute of type Union[Variable, ...].

from pydantic import BaseModel, Union

class Item(BaseModel):
    __root__: Union[Variable, ...]

This model would allow you to create a list or dictionary of Item objects, where each Item object can contain a different type of Variable object. This solution is more flexible than the previous solution, but it is also more complex.

Conclusion:

There are a few different ways to generate a Pydantic model for multiple different objects. The best solution for you will depend on your specific requirements. If you need a simple solution that is easy to implement, then you can use a Union type. If you need a more flexible solution that gives you more control over the structure of your model, then you can use a custom root type.