Python 3.x 组织数据帧，使行值与列名匹配

我正在尝试组织此数据帧，以便相应的行值与列名匹配。我在下面编写的代码适用于前三列，但无法适用于其余列

Company A B  C  D  E F G  H I J K L M

0  Google            A                 
1   Apple         B                    
2   Apple                   C          
3  Google      E                       
4    Lyft                   A

---

def Test(i):

    for columnName in data:
        data[i] = np.where((data[columnName] == i),
                                    data[columnName],
                                    data[i])

        data[columnName] = data[columnName].replace(str(i),'')
 
if __name__ == "__main__":

    columnList = ['A','B','C','E']
    for i in columnList:
        Test(i)