From 4a0a9d7658a7a36c390cb52896a8f6994133dc8e Mon Sep 17 00:00:00 2001
From: unexcellent <>
Date: Wed, 13 Nov 2024 17:07:39 +0100
Subject: [PATCH] feat: Vector subtraction

---
 quantio/vector.py   |  5 +++++
 test/test_vector.py | 18 +++++++++++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/quantio/vector.py b/quantio/vector.py
index 526508a..ca26bfe 100644
--- a/quantio/vector.py
+++ b/quantio/vector.py
@@ -33,6 +33,11 @@ def __add__(self, other: Vector[T] | np.ndarray) -> Vector[T]:
         other_elements = other._elements if isinstance(other, Vector) else np.array(other)
         return Vector[T](self._elements + other_elements)
 
+    def __sub__(self, other: Vector[T] | np.ndarray) -> Vector[T]:
+        """Subtract another vector from this one."""
+        other_elements = other._elements if isinstance(other, Vector) else np.array(other)
+        return Vector[T](self._elements - other_elements)
+
     def __eq__(self, other: object) -> bool:
         """Assess if this object is the same as another."""
         if not isinstance(other, Vector):
diff --git a/test/test_vector.py b/test/test_vector.py
index 6304d05..5f922ac 100644
--- a/test/test_vector.py
+++ b/test/test_vector.py
@@ -2,7 +2,7 @@
 
 import numpy as np
 
-from quantio import Vector, Length, CanNotAddTypesError
+from quantio import Vector, Length, CanNotAddTypesError, CanNotSubtractTypesError
 
 
 def test_init():
@@ -43,5 +43,21 @@ def test_addition__wrong_type():
         vec1 + vec2
 
 
+def test_subtract():
+    vec1: Vector[Length] = Vector([Length(meters=1), Length(meters=2)])
+    vec2: Vector[Length] = Vector([Length(meters=3), Length(meters=3)])
+
+    actual = vec2 - vec1
+    assert actual == Vector([Length(meters=2), Length(meters=1)])
+
+
+def test_subtract__wrong_type():
+    vec1: Vector[Length] = Vector([Length(meters=1), Length(meters=2)])
+    vec2: Vector[float] = Vector([3, 4])
+
+    with pytest.raises(CanNotSubtractTypesError):
+        vec1 - vec2
+
+
 if __name__ == "__main__":
     pytest.main([__file__, "-v"])