对我来说它工作得很好:
df1 = pd.DataFrame({'A':list('abcdef'),
'B':[4,5,4,5,5,4],
'C':[7,8,9,4,2,3],
'D':[1,3,5,7,1,0],
'E':[5,3,6,9,2,4],
'F':list('aaabbb')})
cols_to_use = df1.columns.difference(['A','C'])
print (cols_to_use)
Index(['B', 'D', 'E', 'F'], dtype='object')
print (cols_to_use.append(pd.Index(['complete_name'])))
Index(['B', 'D', 'E', 'F', 'complete_name'], dtype='object')
print (cols_to_use.union(['complete_name']))
Index(['B', 'D', 'E', 'F', 'complete_name'], dtype='object')