Assign string variable to all in group

[Annie Lewis]

I would like to assign a string variable to all in a group. I want to be able to assign "IA" if any member of the group has IA. I want to create the values in newvalue. My data looks like this

id. val. newvalue
1. IA. IA
1. II. IA
1. IA IA
2. II . (missing since no IA for person 2)
2. II .
2 ID .
3. II. IA
3. II IA
3 IA. IA
4. . IA
4. IA. IA
4 ID. IA

[Andrew Musau]

bys id: egen tag= max(inlist(val, "IA"))
gen newval = "IA" if tag

[Nick Cox]

Another way to do it

gen isIA = val == "IA" 

bysort id (isIA) : gen newval = cond(isIA[_N], "IA", "")