["python","python-3.x","python-dataclasses"]
Proper way to create class variable in Data Class

I've just begun playing around with Python's Data Classes, and I would like confirm that I am declaring Class Variables in the proper way. Using regular python classes class Employee: raise_amount = .05 def __init__(self, fname, lname, pay): self.fname = fname self.lname = lname self.pay = pay Using python Data Class @dataclass class Employee: fname: str lname: str pay: int raise_amount = .05 The class variable I am referring to is raise_amount. Is this a properly declared class variable using Data Classes? Or is there a better way of doing so? I have tested the data class implementation already and it provides the expected functionality, but I am mainly wondering if my implementation is following best practices.
To create a class variable, annotate the field as a typing.ClassVar or not at all. from typing import ClassVar from dataclasses import dataclass @dataclass class Foo: ivar: float = 0.5 cvar: ClassVar[float] = 0.5 nvar = 0.5 foo = Foo() Foo.ivar, Foo.cvar, Foo.nvar = 1, 1, 1 print(Foo().ivar, Foo().cvar, Foo().nvar) # 0.5 1 1 print(foo.ivar, foo.cvar, foo.nvar) # 0.5 1 1 print(Foo(), Foo(12)) # Foo(ivar=0.5) Foo(ivar=12) There is a subtle difference in that the unannotated field is completely ignored by @dataclass, whereas the ClassVar field is stored but not converted to an attribute. dataclasses — Data Classes The member variables [...] are defined using PEP 526 type annotations. Class variables One of two places where dataclass() actually inspects the type of a field is to determine if a field is a class variable as defined in PEP 526. It does this by checking if the type of the field is typing.ClassVar. If a field is a ClassVar, it is excluded from consideration as a field and is ignored by the dataclass mechanisms. Such ClassVar pseudo-fields are not returned by the module-level fields() function.