Merge pull request #14800 from mattip/reorder-obj-comparison-loop

ENH: change object-array comparisons to prefer OO->O unfuncs

1 files changed, 14 insertions, 0 deletions

diff --git a/doc/release/upcoming_changes/14800.improvement.rst b/doc/release/upcoming_changes/14800.improvement.rst
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+Comparison on ``object`` dtypes will prefer ``object`` output
+-------------------------------------------------------------
+Comparison ufuncs (``np.equal`` and friends) would return boolean arrays when
+the input array dtype was ``object``. This led to inconsistent behaviour for
+ragged arrays ``a = np.array([1, np.array([1, 2, 3])], dtype=object)``. This
+will now return an object array::
+
+    >>> a = np.array([1, np.array([1, 2, 3])], dtype=object)
+    >>> np.equal(a, a)
+    array([True, array([ True,  True,  True])], dtype=object)
+
+The old behaviour, which will raise a ``ValueError`` in this case, is still
+available by specifying a dtype as ``np.equal(a, a, dtype=bool)``.
+