Not using str with frombytes to ensure Python3 tests pass.

Removing additional instances of using frombytes with str.

Removing additional instances of using frombytes with str.

Author: simnyatsanga

python/pyarrow/pandas_compat.py

@@ -171,7 +171,7 @@ def get_column_metadata(column, name, arrow_type, field_name):
         )
 
     if not isinstance(field_name, six.string_types):
-        field_name = frombytes(str(field_name))
+        field_name = frombytes(field_name)
 
     return {
         'name': name,
@@ -333,7 +333,7 @@ def dataframe_to_arrays(df, schema, preserve_index, nthreads=1):
         if not isinstance(name, six.string_types):
             name = _column_name_to_strings(name)
             if name is not None:
-                name = frombytes(str(name))
+                name = frombytes(name)
 
         if schema is not None:
             field = schema.field_by_name(name)
@@ -567,7 +567,7 @@ def table_to_blockmanager(options, table, memory_pool, nthreads=1,
         for c in columns:
             column_name = c['name']
             if not isinstance(column_name, six.text_type):
-                column_name = frombytes(str(column_name))
+                column_name = frombytes(column_name)
 
             columns_name_dict[c.get('field_name', column_name)] = c['name']