ENH: add OO->? loops, use np.compare(a, b, dtype=bool), add comments

1 files changed, 4 insertions, 0 deletions

diff --git a/numpy/lib/arraysetops.py b/numpy/lib/arraysetops.py
index c30ad534b..cf45e181b 100644
--- a/numpy/lib/arraysetops.py
+++ b/numpy/lib/arraysetops.py
@@ -562,10 +562,14 @@ def in1d(ar1, ar2, assume_unique=False, invert=False):
         if invert:
             mask = np.ones(len(ar1), dtype=bool)
             for a in ar2:
+                # convert object arrays to bool
+                # cannot use np.not_equal until 'S' and 'U' have loops
                 mask &= (ar1 != a).astype(bool)
         else:
             mask = np.zeros(len(ar1), dtype=bool)
             for a in ar2:
+                # convert object arrays to bool
+                # cannot use np.equal until 'S' and 'U' have loops
                 mask |= (ar1 == a).astype(bool)
         return mask