Function replace

Lib/dataclasses.py:1755–1771

Return a new object replacing specified fields with new values. This is especially useful for frozen classes. Example usage:: @dataclass(frozen=True) class C: x: int y: int c = C(1, 2) c1 = replace(c, x=3) assert c1.x == 3 and c1.y == 2

(obj, /, **changes)

def replace(obj, /, **changes):
    """Return a new object replacing specified fields with new values.

    This is especially useful for frozen classes.  Example usage::

      @dataclass(frozen=True)
      class C:
          x: int
          y: int

      c = C(1, 2)
      c1 = replace(c, x=3)
      assert c1.x == 3 and c1.y == 2
    """
    if not _is_dataclass_instance(obj):
        raise TypeError("replace() should be called on dataclass instances")
    return _replace(obj, **changes)


def _replace(self, /, **changes):