added membership functionality for Interval

Author: leslieDLcy

src/pyuncertainnumber/pba/intervals/number.py

@@ -124,6 +124,18 @@ def __iter__(self):  # https://realpython.com/introduction-to-python-generators/
                 break
         pass
 
+    def __contains__(self, item):
+        """Check if an item is enclosed within the interval.
+
+        example:
+            >>> i = Interval(1,3)
+            >>> 2 in i
+            True
+            >>> 4 in i
+            False
+        """
+        return np.all((item >= self.lo) & (item <= self.hi))
+
     def __next__(self):
         pass
 

tests/test_aggregation.py

@@ -42,6 +42,16 @@ def test_env_pbox():
     assert b in t
 
 
+def test_env_intervals():
+    a = pba.I(2, 6)
+    b = pba.I(-2, 9)
+    t = pba.envelope(a, b)
+
+    assert isinstance(t, pba.Interval)
+    # assert a in t
+    # assert b in t
+
+
 # * ----------------------- imposition operation