What are some examples of data validation in Python?

What are some examples of data validation in Python?

Data validation in Python can be done using libraries like Pydantic, Marshmallow, or even custom functions. Would you like examples using a specific library?

Yes, can you show me an example using Pydantic?

Sure! Here's a simple example:

from pydantic import BaseModel, ValidationError

class User(BaseModel):
    name: str
    age: int

try:
    user = User(name='Alice', age=30)
    print(user)
except ValidationError as e:
    print(e.json())

This code defines a User model and validates the data when creating an instance.

What happens if I provide invalid data?

If you provide invalid data, Pydantic will raise a ValidationError. For example, if you set age to a string, it will notify you that the value is not valid.

Can you give me an example of that?

Absolutely! Here's how it looks:

try:
    user = User(name='Alice', age='thirty')
except ValidationError as e:
    print(e.json())

This will output an error message indicating that 'thirty' is not a valid integer.