feat: Vector indexing

quantio/vector.py

@@ -8,7 +8,7 @@
 
 
 class Vector(Generic[T]):
-    """A vector of either quanity or numeric elements."""
+    """An 1 dimensional array of either quantity or numeric elements."""
 
     _elements: np.array
 
@@ -19,3 +19,7 @@ def __init__(self, elements: list | tuple | np.ndarray) -> None:
     def __class_getitem__(cls, *_: object) -> type:
         """Return this class for type hinting."""
         return cls
+
+    def __getitem__(self, index: int) -> T:
+        """Return the element at a specific index."""
+        return self._elements[index]

test/test_vector.py

@@ -15,5 +15,10 @@ def test_init_with_type_hint():
     assert np.all(actual._elements == np.array([Length.zero(), Length.zero()]))
 
 
+def test_indexing():
+    actual: Vector[Length] = Vector([Length(meters=1), Length(meters=2)])
+    assert actual[0] == Length(meters=1)
+
+
 if __name__ == "__main__":
     pytest.main([__file__, "-v"])