Pandas wide format transpose to long format

Question

I have a pandas dataframe like this, with an ID column and a bunch of indicator columns(True/False):

df_have:

ID Male  Special_Need    Teeanger
1    T      F              T
2    F      T              F

I want to transpose it but only for attributes = True. i.e.

df_want:

ID  Attribute
1    Male
1    Teenager
2   Special_Need

Answer 1

Using stack

df.set_index('ID').rename_axis('Attribute',1).stack().loc[lambda x : x=='T'].reset_index().drop(0,1)
Out[268]: 
   ID     Attribute
0   1          Male
1   1      Teeanger
2   2  Special_Need

Answer 2

Using melt:

u = df.melt(id_vars='ID', var_name='Attribute')
u.loc[u.value.eq('T'), ['ID', 'Attribute']]

   ID     Attribute
0   1          Male
3   2  Special_Need
4   1      Teeanger