I’d a vector:

myvec <- c("CERRO_DO_OURO_003F","AQUA_002",TAMOIOS_DELTA_001,URURTUBA_04C) 

I’d like to change the underscore by a rule, for example, if the underscore is followed by a number, I’d like to maintened it like this:

myvecnew
[1] "CERRODOOURO_003F" "AQUA_002" "TAMOIOSDELTA_001" "URURTUBA_04C"

I tried to use gsub, but I’m not able to do it. Could you help me?