合并两列，同时消除pandas数据帧中的重复字符串

import pandas as pd

data = {'Column1': ['A', 'B', 'C', 'D'],
        'Column2': ['B', 'C', 'D', 'E']}
df = pd.DataFrame(data)

df['Merged'] = df['Column1'] + df['Column2']
df['Merged'] = df['Merged'].apply(lambda x: ''.join(sorted(set(x), key=x.index)))

print(df)

  Column1 Column2 Merged
0       A       B     AB
1       B       C    BCA
2       C       D   CDBE
3       D       E     DE