Appending text to a field

I have a field that is free text to user entry. After the request is saved I want either that same field or a computed field to take that value and add a dash and country code (-US) in the 31-33 value of that field. Regardless of what is entered, the dash/country should always all into the 31-33 character values in the field? Thoughts - I’m not savvy with script, @ formula would be helpful… thanks

Subject: appending text to a field

This is a multivalue field?

This is from the designer help and appends the data from fname to the field called full:

@For(n :=1; n<=@Elements(fname); n:= n + 1;

FIELD full := @If(n=1;fname[n] + " " + lname[n];full : (fname[n] + " " + lname[n])));

full

Subject: appending text to a field

thanks for the response… I did see that in the help - what I’m going to is use @length. All entry is at least 10 characters, so I’ll count out the remaining spaces. MIght be a round about way, but for the time being it will suffice