More from explit for loop to a map (should be faster, if not much)

Author: charles-turner-1

intake_esm/cat.py

@@ -516,8 +516,9 @@ def pandas(self) -> pd.DataFrame:
 
         if self.pl_df is not None:
             self.df = self.pl_df.to_pandas(use_pyarrow_extension_array=True)
-            for colname in self.columns_with_iterables:  # Can this be done in one hit?
-                self.df[colname] = self.df[colname].apply(tuple)
+            self.df[list(self.columns_with_iterables)] = self.df[
+                list(self.columns_with_iterables)
+            ].map(tuple)
             return self.df
 
         self.pl_df = self.lf.collect()  # type: ignore[union-attr]