python - Python Pandas:如何返回groupby的成员

我正在为亲戚们在数据框上做一些研究。但是当我找到兄弟时，我无法管理，也找不到将它们全部写下来的方法。下面是一个示例：

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：

          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

我非常感谢您的帮助！

最佳答案

您可以尝试以下方法，首先创建一个Brother列，将所有兄弟作为一个列表，包括其自身，然后分别将其删除。该代码可能已经过优化，但是您可以从以下位置开始：

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               []

关于python - Python Pandas:如何返回groupby的成员，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/38161531/