要获得图示结果,可以使用该函数
concat
创建新数据框的列,如下所示:
new_df = pd.DataFrame()
new_df['COL_1'] = pd.concat([df['COL_1'], df['COL_1']])
new_df['COL_8'] = pd.concat([df['COL_2'], df['COL_4']])
new_df['COL_9'] = pd.concat([df['COL_3'], df['COL_5']])
new_df['COL_10'] = pd.concat([pd.DataFrame(np.repeat('COL_2', len(df))), pd.DataFrame(np.repeat('COL_4', len(df)))])
>>> new_df
COL_1 COL_8 COL_9 COL_10
0 A col2 col3 COL_2
1 B col2 col3 COL_2
2 C col2 col3 COL_2
0 A col4 col5 COL_4
1 B col4 col5 COL_4
2 C col4 col5 COL_4
