Add __contains__() method

Author: antonwolfy

dpnp/dpnp_array.py

@@ -242,7 +242,9 @@ def __bool__(self):
     def __complex__(self):
         return self._array_obj.__complex__()
 
-    # '__contains__',
+    def __contains__(self, key, /):
+        """Return :math:`key in self`."""
+        return (self == key).any()
 
     def __copy__(self):
         """

dpnp/tests/test_ndarray.py

@@ -74,6 +74,39 @@ def test_attributes(self):
         assert_equal(self.two.itemsize, self.two.dtype.itemsize)
 
 
+@testing.parameterize(*testing.product({"xp": [dpnp, numpy]}))
+class TestContains:
+    def test_basic(self):
+        a = self.xp.arange(10).reshape((2, 5))
+        assert 4 in a
+        assert 20 not in a
+
+    def test_broadcast(self):
+        xp = self.xp
+        a = xp.arange(6).reshape((2, 3))
+        assert 4 in a
+        assert xp.array([0, 1, 2]) in a
+        assert xp.array([5, 3, 4]) not in a
+
+    def test_broadcast_error(self):
+        a = self.xp.arange(10).reshape((2, 5))
+        with pytest.raises(
+            ValueError,
+            match="operands could not be broadcast together with shapes",
+        ):
+            self.xp.array([1, 2]) in a
+
+    def test_strides(self):
+        xp = self.xp
+        a = xp.arange(10).reshape((2, 5))
+        a = a[:, ::2]
+        assert 4 in a
+        assert 8 not in a
+        assert xp.full(a.shape[-1], fill_value=2) in a
+        assert xp.full_like(a, fill_value=7) in a
+        assert xp.full_like(a, fill_value=6) not in a
+
+
 class TestView:
     def test_none_dtype(self):
         a = numpy.ones((1, 2, 4), dtype=numpy.int32)