From b6455da7aa3103e5307a8a9c4bc36f6b9e22e61a Mon Sep 17 00:00:00 2001
From: Benjamin Blouin <3keepmovingforward3@users.noreply.github.com>
Date: Sun, 7 Mar 2021 04:50:12 -0500
Subject: [PATCH] Update rt_categorical.py

Handles passing empty list by actually checking if there is one element;
>>>>rt.Cat([1]).isin([])
_categorical_compare_check raise ValueError("List was empty.")
>>> rt.Cat([1]).isin([1])
FastArray([ True])
>>> rt.Cat([1]).isin([2])
FastArray([False])
>>> rt.Cat([1]).isin([1,2])
FastArray([ True])
---
 riptable/rt_categorical.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/riptable/rt_categorical.py b/riptable/rt_categorical.py
index 31b98073..99b6cf5b 100644
--- a/riptable/rt_categorical.py
+++ b/riptable/rt_categorical.py
@@ -3105,8 +3105,8 @@ def isin(self, values) -> FastArray:
         if isinstance(x, (list, np.ndarray)):
             if len(x) > 1:
                 return ismember(self, x)[0]
-            elif np.isscalar(x[0]):
-                return self == x[0]
+            elif np.isscalar(x):
+                return self == x
         return self == x
 
     # -------------------------------------------------------