python - 根据条件更改数据框的值

Question

数据框中的case语句，我在这里做错了什么？

df1['Response'] = [4 if x =='Closed with monetary relief' 
               3 if x =='Closed with non-monetary relief'
               2 if x =='Closed with explanation' 
               1 if x =='Closed' 
               0 if x =='Untimely response' for x in df1['Response']] 

我看到的错误：

3 if x =='以非货币救济关闭' ^ SyntaxError: invalid syntax

Answer 1

我认为这是Series.map字典的最佳用途：

d = {'Closed with monetary relief' : 4,
     'Closed with non-monetary relief':3.
     'Closed with explanation':2,
     'Closed':1,
     'Untimely response':0}

df1['Response'] = df1['Response'].map(d)

如果某些值不匹配得到缺失值，您可以将其替换为原始值：

df1['Response'] = df1['Response'].map(d).fillna(df1['Response'])

或者通过另一个值，例如-1，然后也将值转换为整数，因为至少有一个NaN创建floats 列：

df1['Response'] = df1['Response'].map(d).fillna(-1).astype(int)

Answer 2

试试这种格式，它应该可以工作：

df1.Response.apply(lambda x: 4 if x =='Closed with monetary relief' else
               3 if x =='Closed with non-monetary relief' else
               2 if x =='Closed with explanation' else
               1 if x =='Closed' else
               0 if x =='Untimely response' else None )