"""Demo of dataclass vs non-dataclass performance."""
import timeit
times = 200
dataclass_time = timeit.timeit("""
from dataclasses import dataclass
@dataclass(frozen=True, slots=True)
class Point:
x: float
y: float
z: float
p = Point(1, 2, 3)
""", number=times)
nondataclass_time = timeit.timeit("""
class Point:
__slots__ = ('x', 'y', 'z')
__match_args__ = ('x', 'y', 'z')
def __init__(self, x: float, y: float, z: float) -> None:
object.__setattr__(self, 'x', x)
object.__setattr__(self, 'y', y)
object.__setattr__(self, 'z', z)
def __repr__(self):
cls = type(self).__name__
return f'{cls}(x={self.x!r}, y={self.y!r}, z={self.z!r})'
def __eq__(self, other):
if not isinstance(other, Point):
return NotImplemented
return (self.x, self.y, self.z) == (other.x, other.y, other.z)
def __hash__(self):
return hash((self.x, self.y, self.z))
def __setattr__(self, name, value):
raise AttributeError(f"Can't set attribute {name!r}")
def __delattr__(self, name):
raise AttributeError(f"Can't delete attribute {name!r}")
def __getstate__(self):
return (self.x, self.y, self.z)
def __setstate__(self, state):
fields = ('x', 'y', 'z')
for field, value in zip(fields, state):
object.__setattr__(self, field, value)
p = Point(1, 2, 3)
""", number=times)
print(f"importing 200 dataclasses: {dataclass_time*1000:.0f}ms")
print(f"importing 200 regular classes: {nondataclass_time*1000:.0f}ms")102 views