From 93627a860af56b6e257bf081468f050db0337eb6 Mon Sep 17 00:00:00 2001
From: sapountzis <sapountzis.andreas@gmail.com>
Date: Mon, 18 Dec 2023 10:00:06 +0200
Subject: [PATCH] fix pandas warning

---
 phik/phik.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/phik/phik.py b/phik/phik.py
index 90e29ab..ee70e13 100644
--- a/phik/phik.py
+++ b/phik/phik.py
@@ -196,7 +196,7 @@ def _calc_phik(
     if c0 == c1:
         return c0, c1, 1.0
 
-    datahist = data_binned.groupby([c0, c1])[c0].count().to_frame().unstack().fillna(0)
+    datahist = data_binned.groupby([c0, c1], observed=False)[c0].count().to_frame().unstack().fillna(0)
 
     # If 0 or only 1 values for one of the two variables, it is not possible to calculate phik.
     # This check needs to be done after creation of OF, UF and NaN bins.