三人一组赋值

Question

我正在尝试将assignunique值从pandasdf分组3。对于下面的df，我有一个Column的值，它出现了很多次。我计算这些值中有多少是当前发生的。也就是说，如果它们再次出现，则被认为是在上。你知道吗

如果出现新值，则会增加启用的值数。如果某个值不再出现，则会减少打开的值的数量。

下面是我的尝试。我可以把它分成三组，但它不考虑unique值。你知道吗

import pandas as pd
import numpy as np

d = ({             
   'Place' : ['House 1','House 2','House 3','House 4','House 1','House 2','House 3','House 4'],#,'House 1','House 2']#,'House 4','House 5','House 6','House 7'],                                                                        
   'On' : [1,2,3,4,4,3,2,1],                                                               
     })

df = pd.DataFrame(data=d)

df["Ind"] = np.ceil(df["On"]/3)

Output:

     Place  On    P
0  House 1   1  1.0
1  House 2   2  1.0
2  House 3   3  1.0
3  House 4   4  2.0
4  House 1   4  2.0
5  House 2   3  1.0
6  House 3   2  1.0
7  House 4   1  1.0

预期输出：

     Place  On    P
0  House 1   1  1.0
1  House 2   2  1.0
2  House 3   3  1.0
3  House 4   4  2.0
4  House 1   4  1.0
5  House 2   3  1.0
6  House 3   2  1.0
7  House 4   1  1.0

说明：

区别在于Index 4。Houses 1应该分配给1，因为它们最初分配给这个integer。你知道吗

On列的说明：

Index 0: House 1 is inserted and it appears again = 1 
Index 1: House 2 is inserted and it appears again = 2 
Index 2: House 3 is inserted and it appears again = 3 
Index 3: House 4 is inserted and it appears again = 4 
Index 4: House 1 doesn't appear again so it will decrease number of values on on the next row = 4 
Index 5: House 2 doesn't appear again so it will decrease number of values on  = 3 
Index 6: House 3 doesn't appear again so it will decrease number of values on  = 2 
Index 7: House 4 doesn't appear again so it will decrease number of values on  = 1