List rotating and shuffling

In this chapter you will learn:

Rotate and shuffle a list
Rotate a list

Rotate and shuffle a list

Shuffling a List is useful when we want to change the order of elements in a list. For example, we can output random sequence of a list of string by shuffling the list each time.

static void rotate(List<?> list, int distance) Rotates the elements in the specified list by the specified distance.
static void shuffle(List<?> list) Randomly permutes the specified list using a default source of randomness.
static void shuffle(List<?> list, Random rnd) Randomly permute the specified list using the specified source of randomness.

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
/* java2  s.c  o  m*/
public class Main {

  public static void main(String args[]) {
    List<Character> list = new LinkedList<Character>();

    for (char n = 'A'; n <= 'Z'; n++)
      list.add(n);

    Collections.shuffle(list);

    System.out.print(list);

  }
}

The output:

Rotate a list

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
/*from  j a  v  a2  s  . c o  m*/
public class Main {
  public static void main(String args[]) {
    List<Character> list = new LinkedList<Character>();

    for (char n = 'A'; n <= 'F'; n++)
      list.add(n);

    System.out.println("Here is the original list: ");
    System.out.println(list);
    Collections.rotate(list, 2);

    System.out.println(list);

  }
}