Transfer Vars Between Pydantic Instances

Easily transfer attribute values from one pydantic model instance to another instance.

The Model

Let's say that you have a model and one instance:

>>> from pydantic import BaseModel
>>> class A(BaseModel):
...     field: str
>>> one = A(field="one")
>>> one 

The Tedious Copy

When you wanted to create another instance of the model, you could instatiate and then use the setters:

>>> two = A()
>>> two.field = one.field
>>> two

Or you could set each field in the constructor:

>>> two = A(field=one.field)
>>> two

But what if you have a model with twenty fields? This one-by-one copy is too tedious.

The Convenient Splat Copy

The good news is that you can splat all those 20 fields at once into the new instance.

Use vars() to create a dict of those fields and the ** splat to expand them all into kwargs for the class constructor:

>>> two = A(**vars(one))
>>> two

Any other favorite methods for convenient copying?