Java - Array Shuffle from Array1 to Array 2

Question

Im using Eclipes Android. So here's my array1, and I want it to transfer to another array(array2) randomly. I've been working on it for hours but I can't get it right.

int array1[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
                11,12,13,14,15,16,17,18,19,20,
                21,22,23,24,25,26,27,28,29,30,
                31,32,33,34,35,36,37,38,39,40,
                41,42,43,44,45,46,47,48,49,50};

I want to transfer it to my new array, array2 randomly.

I'm still new to java and still learning.Thanks.

yes, ive been working for 2-3hrs straight and it always crashes my app in the emulator. :( — Bobby Besande Casio, Feb 09 '16 at 15:38
First you copy the array, then you shuffle using Fisher-Yates: https://bost.ocks.org/mike/shuffle — fafl, Feb 09 '16 at 15:38
I've actually asked/answered a question about this (Fisher-Yates) http://stackoverflow.com/questions/35242740/algorithm-function-that-returns-random-number-in-array-in-o1-and-creates-singl — Idos, Feb 09 '16 at 15:39

score 0 · Answer 1 · answered Feb 09 '16 at 15:43

0

Random randomGenerator = new Random();
j = 0;
for (int idx = 1; idx <= 10; ++idx){
  {
   int randomInt = randomGenerator.nextInt(array1.length());
    array2[j] = array1[randomInt];
    j++;
  }
}

this is just an idea proceed accordingly.

answered Feb 09 '16 at 15:43

Akhil

78
12

score 0 · Answer 2 · answered Feb 09 '16 at 15:49

Here's what I would suggest that you do to randomize an array:

for(int i = 0; i < array1.length; i++) {
    int random = (int)(Math.random() * 49 + 1);
    int temp = array1[random];
    array1[random] = array1[i];
    array1[i] = temp;
}

This should randomly shift values around. In each iteration, a random number's element will switch places with the iteration index's element. In you case, you'll have to copy the array into another array before doing the above code.

Java - Array Shuffle from Array1 to Array 2

2 Answers2