String array in java random

Question

String [] rnum = {"Black", "Red", "Black", "Red", "Black", "Red", "Black","Red",
"Black", "Red", "Black", "Red", "Black", "Red", "Black", "Red","Black", "Red", "Green"}; 
int A = rnum.length; 
//the "Math.random() method will get you a random color

int random = (int) (Math.random() * A);  
//randomize the strings  
String Color = rnum[random];

How do i say "if color = black then do this" or same for green or same for red"

Answer 1

You mean...

if(Color.equals("Black")) {
   // then do this
} else if(Color.equals("Red"){
   // then do this
}

or even (In Java >= 1.7)

switch(Color) {
   case "Black":
       // then do this
       break;
   case "Red":
       // then do this
       break;
}

Answer 2

Color should not be capitalized, since that can be a Java class name.

For this purpose you can use a ternary operator (shortened if-else):

String color = ( rnum[random].compareTo("Black") == 0 ? ** do something here ** : ** do something if the color is not "Black" ** );

or:

String color = "";
if(rnum[random].compareTo("Black") == 0) {
    // do stuff
}
else {
    // it's not black. do other stuff.
}

With red and green, just replace "Black" with "Red" , or "Green" .

Answer 3

Using java equals method for each color is the simplest way.

http://docs.oracle.com/javase/7/docs/api/java/lang/String.html#equals%28java.lang.Object%29

Answer 4

Others said the method to decide equality, I would add up something about the algorithm.

Consider adding weight of colours, I see Red and Black appear 9 times while Green appears once. I would add an object containing the name of the colour and the weight you want to apply. Like {"Green", 1}, {"Red", 9}, {"Black", 9}.

Sum up the weights and order the colours in some way and decide where the random number fell.

It would make more clean code and nicer solution.