Easiest way to copy all fields from one dataclass instance to another?

Question

Let\'s assume you have defined a Python dataclass:

@dataclass
class Marker:
    a: float
    b: float = 1.0
         


        

Answer 1

I think that looping over the fields probably is the easiest way. All the other options I can think of involve creating a new object.

from dataclasses import fields

marker_a = Marker(5)
marker_b = Marker(0, 99)

for field in fields(Marker):
    setattr(marker_b, field.name, getattr(marker_a, field.name))

print(marker_b)  # Marker(a=5, b=1.0)