Python Pandas : How do I return members of groupby

Question

我正在为有亲属关系的人做一些数据框架的研究。但当我找到兄弟时，我无法管理，我无法找到一种方法将他们全部写在特定的栏中。下面是一个例子:

cols = ['Name','Father','Brother']
df = pd.DataFrame({'Brother':'',
                   'Father':['Erick Moon','Ralph Docker','Erick Moon','Stewart Adborn'],
                    'Name':['John Smith','Rodolph Ruppert','Mathew Common',"Patrick French"]                   
                  },columns=cols)

df
          Name          Father           Brother
0       John Smith    Erick Moon        
1  Rodolph Ruppert    Ralph Docker        
2    Mathew Common    Erick Moon        
3   Patrick French    Stewart Adborn

我想要的是这样的:

          Name          Father           Brother
0       John Smith    Erick Moon       Mathew Common    
1  Rodolph Ruppert    Ralph Docker        
2    Mathew Common    Erick Moon       John Smith 
3   Patrick French    Stewart Adborn

我感谢任何帮助!

Answer 1

这里有一个你可以尝试的想法，首先创建一个 Brother 列，其中所有兄弟作为一个列表(包括其自身)，然后单独删除其自身。代码可能可以优化，但您可以从哪里开始:

import numpy as np
import pandas as pd
df['Brother'] = df.groupby('Father')['Name'].transform(lambda g: [g.values])
def deleteSelf(row):
    row.Brother = np.delete(row.Brother, np.where(row.Brother == row.Name))
    return(row)
df.apply(deleteSelf, axis = 1)

#              Name         Father          Brother
# 0      John Smith     Erick Moon  [Mathew Common]
# 1 Rodolph Ruppert   Ralph Docker               []
# 2   Mathew Common     Erick Moon     [John Smith]
# 3  Patrick French Stewart Adborn               []