Merge pull request #18369 from AngelGris/bugfix-for-in1d-with-tuples

BUG: np.in1d bug on the object array (issue 17923)

2 files changed, 37 insertions, 0 deletions

diff --git a/numpy/lib/arraysetops.py b/numpy/lib/arraysetops.py
index 6c6c1ff80..eb5c488e4 100644
--- a/numpy/lib/arraysetops.py
+++ b/numpy/lib/arraysetops.py
@@ -565,6 +565,10 @@ def in1d(ar1, ar2, assume_unique=False, invert=False):
     ar1 = np.asarray(ar1).ravel()
     ar2 = np.asarray(ar2).ravel()
 
+    # Ensure that iteration through object arrays yields size-1 arrays
+    if ar2.dtype == object:
+        ar2 = ar2.reshape(-1, 1)
+
     # Check if one of the arrays may contain arbitrary objects
     contains_object = ar1.dtype.hasobject or ar2.dtype.hasobject
 
diff --git a/numpy/lib/tests/test_arraysetops.py b/numpy/lib/tests/test_arraysetops.py
index 847e6cb8a..de2ef255c 100644
--- a/numpy/lib/tests/test_arraysetops.py
+++ b/numpy/lib/tests/test_arraysetops.py
@@ -358,6 +358,39 @@ class TestSetOps:
         result = np.in1d(ar1, ar2)
         assert_array_equal(result, expected)
 
+    def test_in1d_with_arrays_containing_tuples(self):
+        ar1 = np.array([(1,), 2], dtype=object)
+        ar2 = np.array([(1,), 2], dtype=object)
+        expected = np.array([True, True])
+        result = np.in1d(ar1, ar2)
+        assert_array_equal(result, expected)
+        result = np.in1d(ar1, ar2, invert=True)
+        assert_array_equal(result, np.invert(expected))
+
+        # An integer is added at the end of the array to make sure
+        # that the array builder will create the array with tuples
+        # and after it's created the integer is removed.
+        # There's a bug in the array constructor that doesn't handle
+        # tuples properly and adding the integer fixes that.
+        ar1 = np.array([(1,), (2, 1), 1], dtype=object)
+        ar1 = ar1[:-1]
+        ar2 = np.array([(1,), (2, 1), 1], dtype=object)
+        ar2 = ar2[:-1]
+        expected = np.array([True, True])
+        result = np.in1d(ar1, ar2)
+        assert_array_equal(result, expected)
+        result = np.in1d(ar1, ar2, invert=True)
+        assert_array_equal(result, np.invert(expected))
+
+        ar1 = np.array([(1,), (2, 3), 1], dtype=object)
+        ar1 = ar1[:-1]
+        ar2 = np.array([(1,), 2], dtype=object)
+        expected = np.array([True, False])
+        result = np.in1d(ar1, ar2)
+        assert_array_equal(result, expected)
+        result = np.in1d(ar1, ar2, invert=True)
+        assert_array_equal(result, np.invert(expected))
+
     def test_union1d(self):
         a = np.array([5, 4, 7, 1, 2])
         b = np.array([2, 4, 3, 3, 2, 1, 5])