df = pd.DataFrame({"name": ["A001", "A002", "B001", "A001_K", "C002", "B001_K", "B001"],
"protein": [25, 28, 45, 22, 60, 40, 27],
"Qty": [85, 90, 75, 80, 30, 50, 30],
"rank": ["1st", "1st", "1st", "2nd", "1st", "1st", "2nd"]})
请问我想要获取rank列里第二个‘1st'的那行的"Qty"的数（90这个数）要怎么写比较简单
学习下loc：
df.loc[df['rank'] == '1st', 'Qty'][1]