Merge pull request #380 from lincc-frameworks/nested_columns_speedup

speedup nested_columns logic

Author: dougbrn

src/nested_pandas/nestedframe/core.py

@@ -97,16 +97,14 @@ def all_columns(self) -> dict:
     @property
     def nested_columns(self) -> list:
         """retrieves the base column names for all nested dataframes"""
-        nest_cols = []
-        for column in self.columns:
-            if isinstance(self.dtypes[column], NestedDtype):
-                nest_cols.append(column)
-        return nest_cols
+        nested_mask = self.dtypes.apply(lambda dtype: isinstance(dtype, NestedDtype))
+        return self.columns[nested_mask].tolist()
 
     @property
     def base_columns(self) -> list[str]:
         """Returns the list of base (non-nested) column names"""
-        return [col for col in self.columns if col not in self.nested_columns]
+        nested_mask = self.dtypes.apply(lambda dtype: not isinstance(dtype, NestedDtype))
+        return self.columns[nested_mask].tolist()
 
     def _repr_html_(self) -> str | None:
         """Override html representation"""