Pandas - 根据多个条件添加列[重复]

Question

尝试根据两个互斥条件将布尔列添加到 df：

1. df['Type'] == 'CMBX'
2. df['SubType'].isin(['EM','NAHY'])

他们分开工作

df['Px Quoted'] = np.where(df['Type'] =='CMBX', True, False)
df[df['Type']=='CMBX'].head(5)
Out[72]: 
  Batch  Type SubType  Px Quoted
0   NaN  CMBX               True
1   NaN  CMBX               True
2   NaN  CMBX               True
3   NaN  CMBX               True
4   NaN  CMBX               True

或

df['Px Quoted'] = np.where(df['SubType'].isin(['EM','NAHY']), True, False)

df[df['SubType']=='EM'].head(5)
Out[74]: 
     Batch Type SubType  Px Quoted
21  NY1530  CDX      EM       True
29  NY1530  CDX      EM       True
36  NY1530  CDX      EM       True
43  NY1530  CDX      EM       True
50  NY1530  CDX      EM       True

但以下没有

df['Px Quoted'] = np.where(df['Type'] =='CMBX' or df['SubType'].isin(['EM','NAHY']), True, False)

ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().

不知道为什么它是模棱两可的，因为类型 CMBX 不能包含任何子类型 ['EM','NAHY'] 任何想法？是因为它的 Subtype 是空白的吗？

Answer 1

np.where 需要使用位运算符：

df['Px Quoted'] = np.where((df['Type'] =='CMBX') | (df['SubType'].isin(['EM','NAHY'])), True, False)

在这里，我将or 更改为|