How to generate class's __init__ method from declared descriptors?
The example from python's documentation:
class Component:
name = String(minsize=3, maxsize=10, predicate=str.isupper)
kind = OneOf('wood', 'metal', 'plastic')
quantity = Number(minvalue=0)
def __init__(self, name, kind, quantity):
self.name = name
self.kind = kind
self.quantity = quantity
How can I make python to generate __init__
method for me?
You can use python's dataclasses and it will work just fine:
from dataclasses import dataclass
@dataclass
class Component:
name: str = String(minsize=3, maxsize=10, predicate=str.isupper)
kind: str = OneOf('wood', 'metal', 'plastic')
quantity: int = Number(minvalue=0)
Example:
try:
Component(name="Log", kind="wood", quantity=3)
except ValueError as e:
print(e)
Expected <method 'isupper' of 'str' objects> to be true for 'Log'
c = Component(name="LOG", kind="wood", quantity=3)
[c.name, c.kind, c.quantity]
['LOG', 'wood', 3]
I found it very useful when dealing with classes which act as data containters with MANY descriptor-fields.