Creating new variable across rows

[Johanna Riha]

Hello,

I'm trying to create the following 'new_var' by concatenating the radio_show entries by id. Any help with how to go about this would be greatly appreciated.

id	radio_show	new_var
acc	1	123
acc	2	123
acc	3	123
hg	2	24
hg	2	24
tgc	5	544
tgc	5	544
bvv	4	4
nnc	2	2

Thanks
Johanna

[Nick Cox]

gen wanted = "" 
bysort id (radio_show) : replace wanted = wanted[_n-1] + string(radio_show) 
by id: replace wanted = wanted[_N]

[Johanna Riha]

Thank you so much Nick!