我有一个数据框，其中包含对马匹的投注，每一行都是新的投注。每个投注具有多个属性，包括位置，马的名字，赢/输等。 问题在于，那些下注的奖金以正整数给出，并且提供了flag属性以说明是赢还是输。
这是提供的数据框：
Race Course Horse Year Month Date Amount Won/Lost
0 Aintree Red Rum 2017 5 12 11.58 won
1 Punchestown Camelot 2016 12 22 122.52 won
2 Sandown Beef of Salmon 2016 11 17 20.00 lost
3 Ayr Corbiere 2016 11 3 25.00 lost
4 Fairyhouse Red Rum 2016 12 2 65.75 won
5 Ayr Camelot 2017 3 11 12.05 won
6 Aintree Hurricane Fly 2017 5 12 11.58 won
7 Punchestown Beef or Salmon 2016 12 22 112.52 won
8 Sandown Aldaniti 2016 11 17 10.00 lost
9 Ayr Henry the Navigator 2016 11 1 15.00 lost
10 Fairyhouse Jumanji 2016 10 2 65.75 won
11 Ayr Came Second 2017 3 11 12.05 won
12 Aintree Murder 2017 5 12 5.00 lost
13 Punchestown King Arthur 2016 6 22 52.52 won
14 Sandown Filet of Fish 2016 11 17 20.00 lost
15 Ayr Denial 2016 11 3 25.00 lost
16 Fairyhouse Don't Gamble 2016 12 12 165.75 won
17 Ayr Ireland 2017 1 11 22.05 won
我需要创建以下格式的数据框：
Year Total Won Total Lost
2016 €123.45 €678.90
2017 €543.21 €987.60
我一直在尝试遍历各列，并尝试使用where函数，但似乎无法使任何事情起作用。
答案 0 :(得分：4)
使用groupby，sum，然后堆叠结果：
df.groupby(['Year', 'Won/Lost'])['Amount'].sum().unstack(-1).add_prefix('total_')
Won/Lost total_lost total_won
Year
2016 115.0 584.81
2017 5.0 69.31