precompute set

apache · Jan 24, 2018 · 54c5bf5 · 54c5bf5
1 parent b7e0560
commit 54c5bf5
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/python/pyarrow/pandas_compat.py b/python/pyarrow/pandas_compat.py
@@ -340,10 +340,11 @@ def dataframe_to_arrays(df, schema, preserve_index, nthreads=1):
         convert_types.append(type)
         column_names.append(name)
 
+    column_names_set = set(column_names)
     for i, column in enumerate(index_columns):
         columns_to_convert.append(column)
         convert_types.append(None)
-        name = _index_level_name(column, i, column_names)
+        name = _index_level_name(column, i, column_names_set)
         index_column_names.append(name)
 
     # NOTE(wesm): If nthreads=None, then we use a heuristic to decide whether