Pandasデータフレームを加工し、別のデータフレームを作成したい

Python

import pandas as pd import numpy as np df = pd.DataFrame( data=np.array([["Japan", 20, 8, 30, 26], ["America", 20, 18, 30, 4], ["Japan", 20, 12, 30, 28], ["Japan", 20, 17, 30, 25], ["America", 20, 19, 30, 18], ["America", 20, 16, 30, 20], ["Japan", "", "", 30, 30], ["Japan", 20, 13, 30, 25], ["China", 20, 16, 30, 24], ["America", 20, 20, "", ""], ["Japan", 20, 5, 30, 25], ["Japan", 20, 14, 30, 25], ["America", 20, 15, 30, 20], ["Japan", 20, 8, 30, 18], ["America", "", "", 30, 7]]), columns=['国', '英語問題数', '英語正答数', '国語問題数', '国語正答数'] )