Transpose and keep a column name

I have a dataframe with the following information:

data = {'Code':['xxy','zzy', 'rrr'], 
        'Service':["23a","22c","21d"],
        'Service2':["44e", "32c","85a"],
        'Service3':["42e", "32z","8m"],
       }
df = pd.DataFrame(data)
df

It looks like this
table

and i would like it to look like this

expected

please your help, thanks!

>Solution :

df.set_index('Code').stack().reset_index()[['Code', 0]]

result:

   Code 0
0   xxy 23a
1   xxy 44e
2   xxy 42e
3   zzy 22c
4   zzy 32c
5   zzy 32z
6   rrr 21d
7   rrr 85a
8   rrr 8m

if you want change column name, use following code(including full code):

df.set_index('Code').stack().reset_index()[['Code', 0]].rename(columns={0:'as you wish'})


    Code    as you wish
0   xxy     23a
1   xxy     44e
2   xxy     42e
3   zzy     22c
4   zzy     32c
5   zzy     32z
6   rrr     21d
7   rrr     85a
8   rrr     8m