Selecting randomly from a string array

Question

I have run into a little problem. I have a homework exercise where i need to 'randomly' select a string from a string array. The goal of the exercise is to make a code which choses a random (inserted) name. My code:

 public void run() {
        int userSelection = -1;
        int userAmount = 0;
        String[] users = new String[userAmount];
        int[] amountChosen = new int[userAmount];

        while (userSelection != 0) {
            drawMenu();
            System.out.println();

            //user selecting the menu choice
            System.out.print("Make a selection from the menu: ");
            userSelection = userInput();
            System.out.println();

            //forcing the user to give one of the allowed values
            while (userSelection < 0 || userSelection > 4) {
                System.out.print("That is invalid input. try again: ");
                userSelection = userInput();
            }

            //adding users
            if (userSelection == 1) {
                System.out.print("How many users do we have?");
                userAmount = userInput();
                users = new String[userAmount];
                amountChosen = new int[userAmount];
                addUsers(users, userAmount); //returns user array with names
                System.out.println();
            }

            //selecting random user
             else if (userSelection == 2) {
                int playerSelect = (int) (Math.random()*userAmount);
                amountChosen[playerSelect]++;
                System.out.println(users[playerSelect] + " was chosen!");
                System.out.println();
            }

            //display the amount the users were chosen
            else{
                System.out.println("******** Turns ********");
                for (int i = 0; i < userAmount; i++){
                    System.out.println("* " + "[" + amountChosen[i] + "] " + users[i]);
                }
                System.out.println("***********************");
                System.out.println();
            }
        }
    }

As you can see i now have a totally random userselection. For keeping tabs on how often a player is chosen i already made the 'int[] amountChosen' array. The goal is to "select a random player, also make it chose the player that is chosen the fewest times" so basicly it needs to select the string with the lowest amountChosen. (Also: I am aware my code may be a little bit messy and weird in some places. I just started learning java) Thank you for response!

Choosing a random player is not choosing a set player or lowest chosen player. Now you can do a random set if there is more than 1 player that has been choose the lowest amount of times. Is this what you are trying to accomplish? — David Coler
– David Coler, Commented Oct 11, 2018 at 21:12

ninja.coder · Accepted Answer · 2018-10-11 21:16:10Z

4

I won't give out the answer to your assignment. But, here is a naive implementation of what you are trying to achieve:

private void someMethod() {
    String[] strArray = {"foo", "bar", "foobar"};
    Random random = new Random();
    System.out.println(strArray[random.nextInt(strArray.length)]);
}

Explanation:

You take a random number between 0 and the length of your string array using Random and then just use this as an index to query your string array.

answered Oct 11, 2018 at 21:16

ninja.coder

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Comments

MC Emperor · Accepted Answer · 2018-10-11 21:40:08Z

If I understand correctly, you want to pick randomly one of all players having the lowest amount chosen?

Use a Map<String, Integer> with the amounts;
Filter the map with all players with the lowest amount;
Use Random.nextInt(amountOfLowest).

You could use Java Streams.

Hints: • use map.entrySet().stream() to stream over the map elements • use values(), unboxed() and min() to get the lowest value • use filter(), map() and collect() to collect a list of all players with the lowest amount • use List.get(new Random().nextInt(...)) to select a player.

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