feat: extend Vector.to_numpy() to include units

generate/generate_boilerplate.py

@@ -22,6 +22,9 @@ def generate_boilerplate(quantities_with_fields: dict[str, dict[str, str]]) -> N
             current_line_is_part_of_autogenerated_code = True
             target_content_with_boilerplate.append(line)
             target_content_with_boilerplate.append("")
+            target_content_with_boilerplate.extend(
+                _generate_base_unit(current_class, quantities_with_fields[current_class])
+            )
             target_content_with_boilerplate.extend(
                 _generate_properties(current_class, quantities_with_fields[current_class])
             )
@@ -46,6 +49,19 @@ def generate_boilerplate(quantities_with_fields: dict[str, dict[str, str]]) -> N
         target_file.writelines(target_content_with_boilerplate)
 
 
+def _generate_base_unit(current_class: str, units: dict[str, str]) -> list[str]:
+    base_unit = None
+    for unit, factor in units.items():
+        if float(eval(factor)) == 1:
+            base_unit = unit
+            break
+
+    if base_unit is None:
+        raise ValueError(f"{current_class} needs a unit with factor equal to 1.")
+
+    return [f'    _BASE_UNIT = "{base_unit}"', ""]
+
+
 def _generate_properties(current_class: str, units: dict[str, str]) -> list[str]:
     code = []
 

quantio/__init__.py

@@ -1,6 +1,6 @@
 """The main quantio package."""
 
-from .exceptions import CanNotAddTypesError, CanNotSubtractTypesError
+from .exceptions import CanNotAddTypesError, CanNotSubtractTypesError, NoUnitSpecifiedError
 from .quantities import Acceleration, Angle, Area, Length, Mass, Time, Velocity
 from .vector import Vector
 
@@ -15,4 +15,5 @@
     "Vector",
     "CanNotAddTypesError",
     "CanNotSubtractTypesError",
+    "NoUnitSpecifiedError",
 ]

quantio/_quantity_base.py

@@ -11,6 +11,9 @@ class _QuantityBase(ABC):
     _base_value: float
     "The base unit of the quantity."
 
+    _BASE_UNIT: str
+    "Name of the unit with a factor of 1."
+
     def __eq__(self, other: object) -> bool:
         """Assess if this object is the same as another."""
         if isinstance(other, type(self)):

quantio/exceptions.py

@@ -10,3 +10,13 @@ class CanNotSubtractTypesError(TypeError):
 
     def __init__(self, self_type_descriptor: str, other_type_descriptor: str) -> None:
         super().__init__(f"Can not subtract {other_type_descriptor} from {self_type_descriptor}")
+
+
+class NoUnitSpecifiedError(TypeError):
+    """Raised when a Vector[_QuantityBase] is converted to a np.array without specifying a unit."""
+
+    def __init__(self) -> None:
+        super().__init__(
+            "When a vector with quantity elements is converted into a numpy array, a unit must be "
+            "specified."
+        )

quantio/quantities.py

@@ -8,6 +8,8 @@ class Acceleration(_QuantityBase):
 
     # --- This part is auto generated. Do not change manually. ---
 
+    _BASE_UNIT = "meters_per_square_second"
+
     @property
     def meters_per_square_second(self) -> float:
         """The acceleration in meters per square second."""
@@ -40,6 +42,8 @@ class Angle(_QuantityBase):
 
     # --- This part is auto generated. Do not change manually. ---
 
+    _BASE_UNIT = "radians"
+
     @property
     def degrees(self) -> float:
         """The angle in degrees."""
@@ -72,6 +76,8 @@ class Area(_QuantityBase):
 
     # --- This part is auto generated. Do not change manually. ---
 
+    _BASE_UNIT = "square_meters"
+
     @property
     def square_miles(self) -> float:
         """The area in square miles."""
@@ -146,6 +152,8 @@ class Length(_QuantityBase):
 
     # --- This part is auto generated. Do not change manually. ---
 
+    _BASE_UNIT = "meters"
+
     @property
     def miles(self) -> float:
         """The length in miles."""
@@ -220,6 +228,8 @@ class Mass(_QuantityBase):
 
     # --- This part is auto generated. Do not change manually. ---
 
+    _BASE_UNIT = "kilograms"
+
     @property
     def tonnes(self) -> float:
         """The mass in tonnes."""
@@ -287,6 +297,8 @@ class Velocity(_QuantityBase):
 
     # --- This part is auto generated. Do not change manually. ---
 
+    _BASE_UNIT = "meters_per_second"
+
     @property
     def meters_per_second(self) -> float:
         """The velocity in meters per second."""
@@ -326,6 +338,8 @@ class Time(_QuantityBase):
 
     # --- This part is auto generated. Do not change manually. ---
 
+    _BASE_UNIT = "seconds"
+
     @property
     def hours(self) -> float:
         """The time in hours."""

quantio/vector.py

@@ -5,6 +5,7 @@
 import numpy as np
 
 from ._quantity_base import _QuantityBase
+from .exceptions import NoUnitSpecifiedError
 
 T = TypeVar("T")
 
@@ -17,13 +18,12 @@ class Vector(Generic[T]):
     def __init__(self, elements: list | tuple | np.ndarray) -> None:
         self._elements = np.array(elements)
 
-    def to_numpy(self) -> np.ndarray[float]:
+    def to_numpy(self, unit: str | None = None) -> np.ndarray[float]:
         """Convert this vector into a numpy array of floats."""
-        if len(self._elements) == 0:
-            return np.array([])
-
         if isinstance(self._elements[0], _QuantityBase):
-            return np.array([element._base_value for element in self._elements])
+            if unit is None:
+                raise NoUnitSpecifiedError
+            return np.array([getattr(element, unit) for element in self._elements])
 
         return np.array([float(element) for element in self._elements])
 
@@ -52,11 +52,19 @@ def __sub__(self, other: Vector[T] | np.ndarray) -> Vector[T]:
 
     def __mul__(self, other: Vector | np.ndarray | float) -> np.ndarray:
         """Multipy this vector with either another vector or a scalar."""
-        return self.to_numpy() * _other_to_numpy(other)
+        if isinstance(self._elements[0], _QuantityBase):
+            self_to_numpy = self.to_numpy(self._elements[0]._BASE_UNIT)
+        else:
+            self_to_numpy = self.to_numpy()
+        return self_to_numpy * _other_to_numpy(other)
 
     def __truediv__(self, other: Vector | np.ndarray | float) -> np.ndarray:
         """Multipy this vector with either another vector or a scalar."""
-        return self.to_numpy() / _other_to_numpy(other)
+        if isinstance(self._elements[0], _QuantityBase):
+            self_to_numpy = self.to_numpy(self._elements[0]._BASE_UNIT)
+        else:
+            self_to_numpy = self.to_numpy()
+        return self_to_numpy / _other_to_numpy(other)
 
     def __eq__(self, other: object) -> bool:
         """Assess if this object is the same as another."""
@@ -74,6 +82,8 @@ def _other_to_numpy(other: Vector | np.ndarray | float) -> np.ndarray:
         return np.array([other._base_value])
 
     if isinstance(other, Vector):
+        if isinstance(other._elements[0], _QuantityBase):
+            return other.to_numpy(other._elements[0]._BASE_UNIT)
         return other.to_numpy()
 
     if isinstance(other, np.ndarray):

test/test_vector.py

@@ -2,7 +2,13 @@
 
 import numpy as np
 
-from quantio import Vector, Length, CanNotAddTypesError, CanNotSubtractTypesError
+from quantio import (
+    Vector,
+    Length,
+    CanNotAddTypesError,
+    CanNotSubtractTypesError,
+    NoUnitSpecifiedError,
+)
 
 
 def test_init():
@@ -155,5 +161,26 @@ def test_divide__wrong_dimension():
         vec1 / vec2
 
 
+def test_to_numpy__floats():
+    vec: Vector[float] = Vector([0.0, 1.0])
+
+    actual = vec.to_numpy()
+    assert np.all(actual == np.array([0.0, 1.0]))
+
+
+def test_to_numpy__quantity():
+    vec: Vector[Length] = Vector([Length(meters=1), Length(meters=2), Length(meters=3)])
+
+    actual = vec.to_numpy("centimeters")
+    assert np.all(actual == np.array([100.0, 200.0, 300.0]))
+
+
+def test_to_numpy__quantity_no_unit():
+    vec: Vector[Length] = Vector([Length(meters=1), Length(meters=2), Length(meters=3)])
+
+    with pytest.raises(NoUnitSpecifiedError):
+        vec.to_numpy()
+
+
 if __name__ == "__main__":
     pytest.main([__file__, "-v"])