我有以下NFL跟踪数据：
Event PlayId FrameId x-coord y-coord
0 Start 1 1 20.2 20.0
1 NaN 1 2 21.0 19.1
2 NaN 1 3 21.3 18.3
3 NaN 1 4 22.0 17.5
4 End 1 5 22.5 17.2
4 NaN 1 6 22.5 17.2
4 NaN 1 7 22.5 17.2
4 NaN 1 8 22.5 17.2
4 NaN 1 9 22.5 17.2
4 NaN 1 10 22.5 17.2
5 NaN 2 1 23.0 16.9
6 Start 2 2 23.6 16.7
7 End 2 3 25.1 34.1
8 NaN 2 4 25.9 34.2
10 NaN 3 1 22.7 34.2
11 Nan 3 2 21.5 34.5
12 NaN 3 3 21.1 37.3
13 Start 3 4 21.2 44.3
14 NaN 3 5 20.4 44.6
15 End 3 6 21.9 42.7
如何过滤此列表以仅获取“事件”列的“开始”和“结束”值之间的行？为了澄清，这是我要过滤的数据：
Event PlayId FrameId x-coord y-coord
0 Start 1 1 20.2 20.0
1 NaN 1 2 21.0 19.1
2 NaN 1 3 21.3 18.3
3 NaN 1 4 22.0 17.5
4 End 1 5 22.5 17.2
6 Start 2 2 23.6 16.7
7 End 2 3 25.1 34.1
13 Start 3 4 21.2 44.3
14 NaN 3 5 20.4 44.6
15 End 3 6 21.9 42.7
显式解决方案将不起作用，因为实际数据集非常大，并且无法预测起始值和结束值的落差。
答案 0 :(得分：2)
先用slice和ffill然后再用concat返回，在df中也有Nan，应该是NaN吗？
df1=df.copy()
newdf=pd.concat([df1[df.Event.ffill()=='Start'],df1[df.Event=='End']]).sort_index()
newdf
Event PlayId FrameId x-coord y-coord
0 Start 1 1 20.2 20.0
1 NaN 1 2 21.0 19.1
2 NaN 1 3 21.3 18.3
3 NaN 1 4 22.0 17.5
4 End 1 5 22.5 17.2
6 Start 2 2 23.6 16.7
7 End 2 3 25.1 34.1
13 Start 3 4 21.2 44.3
14 NaN 3 5 20.4 44.6
15 End 3 6 21.9 42.7
或
newdf=df[~((df.Event.ffill()=='End')&(df.Event.isna()))]
newdf
Event PlayId FrameId x-coord y-coord
0 Start 1 1 20.2 20.0
1 NaN 1 2 21.0 19.1
2 NaN 1 3 21.3 18.3
3 NaN 1 4 22.0 17.5
4 End 1 5 22.5 17.2
6 Start 2 2 23.6 16.7
7 End 2 3 25.1 34.1
13 Start 3 4 21.2 44.3
14 NaN 3 5 20.4 44.6
15 End 3 6 21.9 42.7