Python 在某些条件下转置数据帧

我有一个数据帧，示例如下-

      UserId      UserName     Temp     Values       City     Country

 1    jsmith     James Smith     x        20        London     UK
 2    msmith     Michael Smith   y        25        Chicago    US
 3    mgarcia    Maria Garcia    z        60        Delhi      India

      UserId      UserName      Values 

 1    jsmith     James Smith      20
 2    jsmith     James Smith    London
 3    jsmith     James Smith      UK
 4    msmith     Michael Smith    25
 5    msmith     Michael Smith  Chicago
 6    msmith     Michael Smith    US
 7    mgarcia    Maria Garcia     60
 8    mgarcia    Maria Garcia    Delhi
 9    mgarcia    Maria Garcia    India

我想创建一个新的数据框，在这个数据框中，我想在新的数据框中保留UserID和UserName列，而不想将列Temp和From值转换为我想转换该列的Country列。我尝试了各种方法，但都没有成功。我需要最终输出如下-

      UserId      UserName     Temp     Values       City     Country

 1    jsmith     James Smith     x        20        London     UK
 2    msmith     Michael Smith   y        25        Chicago    US
 3    mgarcia    Maria Garcia    z        60        Delhi      India

      UserId      UserName      Values 

 1    jsmith     James Smith      20
 2    jsmith     James Smith    London
 3    jsmith     James Smith      UK
 4    msmith     Michael Smith    25
 5    msmith     Michael Smith  Chicago
 6    msmith     Michael Smith    US
 7    mgarcia    Maria Garcia     60
 8    mgarcia    Maria Garcia    Delhi
 9    mgarcia    Maria Garcia    India

如何做到这一点

res = (df.set_index(['UserId','UserName'])
       .drop('Temp',axis=1)
       .stack()
       .droplevel(-1)
       .reset_index(name='Values')
      )

res

    UserId  UserName    Values
0   jsmith  James Smith 20
1   jsmith  James Smith London
2   jsmith  James Smith UK
3   msmith  Michael Smith   25
4   msmith  Michael Smith   Chicago
5   msmith  Michael Smith   US
6   mgarcia Maria Garcia    60
7   mgarcia Maria Garcia    Delhi
8   mgarcia Maria Garcia    India