Java Regex : String Formatting

Question

After runing this

Names.replaceAll("^(\\w)\\w+", "$1.")

I have a String Like

Names = F.DA, ABC, EFG

I want a String format like

F.DA, A.BC & E.FG

How do I do that ?

Update :

If I had a name Like

Robert Filip, Robert Morris, Cirstian Jed

I want like

R.Filp, R.Morris & C.Jed

I will be happy, If also you suggest me a good resource on JAVA Regex.

Answer 1

You need to re-assign the result back to Names, since Strings are immutable, the replaceAll methods does not do in place replacement, rather it returns a new String:

names = names.replaceAll(", (?=[^,]*$)", " & ")

Answer 2

Following should work for you:

 String names = "Robert Filip, Robert Morris, Cirstian Jed, S.Smith";
 String repl  = names.replaceAll("((?:^|[^A-Z.])[A-Z])[a-z]*\\s(?=[A-Z])", "$1.")
                     .replaceAll(", (?=[^,]*$)", " & ");

 System.out.println(repl); //=> R.Filip, R.Morris, C.Jed & S.Smith

Explanation:

1. 1st replaceAll call is matching a non-word && non-dot character + a capital letter in group #1 + 0 or more lower case letters + a space which should be followed by 1 capital letter. It is then inserting a dot in front of the match $1.
2. 2ns replaceAll call is matching a comma that is not followed by another comma and replacing that by literal string " & ".

Answer 3

Try this

    String names = "Amal.PM , Rakesh.KR , Ajith.N";
    names = names.replaceAll(" , (?=[^,]*$)", " & ");
    System.out.println("New String : "+names);