I have a list of strings of this kind:
f<-c("CC 982","RX 112","TR 002","FF 1328")
I need to add a leading 0, as with the str_pad function, at the beginning of the numerical portion, to get to this:
"CC 0982" "RX 0112" "TR 0002" "FF 1328"
For now, I have tried with sub
sub('(.{2})(.{1})(.{3})', "\\1\\20\\3", f)
Close enough, but I don't want the leading 0 if the numerical string has 4 digits. What is the solution here? Thank you