python numpy创建数据集列：仅根据条件添加值，否则为null

Question

我尝试创建列终止日期。但只有当标志“取消”或“失效”设置为“是”时，列终止日期才应包含生效日期，否则为空。对于这三种方法，我收到以下错误消息

df['Termination_Date'] = np.where((df['Cancellations'] == 'Yes') | (df['Lapses'] == 'Yes'), df['Effective Date'])
ValueError: either both or neither of x and y should be given

df['Termination_Date'] = np.where((df['Cancellations'] == 'Yes') | (df['Lapses'] == 'Yes'), df['Effective Date'], "")
TypeError: invalid type promotion

df['Termination_Date'] = np.where((df['Cancellations'] == 'Yes') | (df['Lapses'] == 'Yes'), df['Effective Date'], np.nan)
TypeError: invalid type promotion

谢谢

Answer 1

使用^{}：

df['Termination_Date'] = df['Effective Date'].where( (df['Cancellations'] == 'Yes') |
                                                     (df['Lapses'] == 'Yes') )

或^{}

df['Termination_Date'] = df['Effective Date'].mask( df['Cancellations'].ne('yes')
                                              .mul(df['Lapses'].ne('Yes') )

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我们也可以用^{}检查

df['Termination_Date'] = df['Effective Date'].where( df[['Lapses','Cancellations']].eq('Yes').any(axis = 1) )