Re: selecting random array elements

From:
Lew <noone@lewscanon.com>
Newsgroups:
comp.lang.java.help
Date:
Sat, 08 Aug 2009 01:10:32 -0400
Message-ID:
<h5j1c9$o9d$1@news.albasani.net>
markspace wrote:

oc2052 wrote:

I am very new to Java and programming in general, and was hoping
someone could point me in the right direction with this. I am writing
a program consisting of a String array (the elements are lines of
text) and Id like to randomly pull an element from the array and
display it. I havent been able to figure out how to utilize the
java.util.random for this particular case. Thanks in advance for any
help


Just use "new Random()" to make a random object, then call "nextInt()"
on it to get a suitable random index.

Something like this:

package fubar;
import java.util.ArrayList;
import java.util.Random;

public class RandomArray {

    public static void main( String[] args )
    {
        ArrayList<String> list = new ArrayList<String>();
        Random rand = new Random();

        String element = list.get( rand.nextInt( list.size() ) );
    }
}


Or:

  public class RandomGetter
  {
    private final Random rand = new Random();
    // presumably not thread safe

    private List <String> stuff = new ArrayList <String> ();

    public RandomGetter()
    {
      // fill stuff here
    }

    public String getRandom()
    {
      return stuff.get( rand.nextInt( stuff.size() ));
    }

    public static void main( String [] args )
    {
      RandomGetter rander = new RandomGetter();
      String element = rander.getRandom();
      System.out.println( "Random element = \""+ element +"\"" );
    }
  }

--
Lew

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