Update janitor/functions/concatenate_columns.py

Fu-Jie · Zeroto521 · web-flow · commit 30c1f3c8dc9d · 2022-09-13T10:23:09.000+08:00
Co-authored-by: 40% &lt;Zeroto521@gmail.com&gt;
diff --git a/janitor/functions/concatenate_columns.py b/janitor/functions/concatenate_columns.py
@@ -51,6 +51,7 @@ def concatenate_columns(
     if len(column_names) < 2:
         raise JanitorError("At least two columns must be specified")
 
+    df = df.copy()  # avoid mutating original data
     df[new_column_name] = (
         df[column_names]
         .astype(str)
