Scanner input = new Scanner(System.in);
String[] colors = {"R", "G", "B", "P", "O", "Y"};
String guess = "";
String valid = false;
//Get Input
guess = input.nextLine().toUpperCase();
// Change String Array to Regular String
String Colors = "";
for(int i=0; i<colors.length; i++) {
    Colors += colors[i];
}
// See if Guess Consists out of Correct Letters
if(guess.matches(Colors)) {
    valid = true;
}
Basically what I want to achieve with this code is to check if the input given meets the requirements.
In this case does guess only consists of the letters given in colors, for example:
if guess = RGB then valid = true
if guess = RGBA then valid = false
I know I can also put it in manually like this:
if(guess.matches("[RGBPOY]+")) {
    valid = true;
}
But I want to keep it procedural.
Is there a way to get this working? Or am I better off using a different method like say a for loop?
I only recently started with JAVA and am not yet familiar with all the different approaches it has to offer.
 
     
     
    