Need help on Random Selection of value

[shaik_irfan]

Hi,

I have a system property from where i wanted to pick only 2 random values every time.

I am able to pick one value but can anyone please help me how to pick 2 random values every time ?

var tbl = gs.getProperty('random.generator');
gs.print(tbl);
var numRes = tbl.split(',');
var returnNum = 2;
var random = Math.floor((Math.random() * numRes.length));
var sys_id = numRes[random];
gs.print(sys_id)

Ouput:

*** Script: a,b,c,d,e
*** Script: d


But i wanted to display 2 values like a,b or b,d or a,c 

[Ankur Bawiskar]

Hi,

sample code below

var tbl = gs.getProperty('random.generator');
gs.print(tbl);
var numRes = tbl.split(',');

var val = getRandom(numRes,2);

gs.info('Random values are: ' + val);

function getRandom(arr, n) {
    var result = new Array(n),
        len = arr.length,
        taken = new Array(len);
    if (n > len)
               return 'getRandom: more elements taken than available';
    while (n--) {
        var x = Math.floor(Math.random() * len);
        result[n] = arr[x in taken ? taken[x] : x];
        taken[x] = --len in taken ? taken[len] : len;
    }
    return result;
}

Script:

var arr = ['a','b','c','d'];

var val = getRandom(arr,2);

gs.info(val);

function getRandom(arr, n) {
    var result = new Array(n),
        len = arr.length,
        taken = new Array(len);
    if (n > len)
       return 'getRandom: more elements taken than available';
    while (n--) {
        var x = Math.floor(Math.random() * len);
        result[n] = arr[x in taken ? taken[x] : x];
        taken[x] = --len in taken ? taken[len] : len;
    }
    return result;
}

Output:

If my answer solved your issue, please mark my answer as ✅ Correct & 👍Helpful based on the Impact.

Regards
Ankur

[shaik_irfan]

@Ankur Bawiskar 

Too difficult for me to understand if you dont mind can you please explain with the comments what you are doing ?

[Ankur Bawiskar · Accepted solution]

Hi Shaik,

simpler code and explanation:

var finalArray = randomElements();

gs.info('finalArray is:' + finalArray);

function randomElements() {
  var finalArr = [];
 
  var tbl = gs.getProperty('random.generator');
  var numRes = tbl.split(',');
  var returnNum = 2; // give here how many random elements you want
 
  if(returnNum > numRes.length)
   return 'more elements taken than available';

  for (var i = 0; i < returnNum; i++) {
    var rand = numRes[Math.floor(Math.random() * numRes.length)];
    finalArr.push(rand.toString());
  }
  return finalArr.join(",");
}

Explanation:

It first checks if number of random elements asked is less than array length

1) since you want 2 random elements the for loop runs for 2 times

2) each time it generates a random number and then uses that as index to determine the array element

3) it then pushes that value in final array and then returns that final array

Mark ✅ Correct if this solves your issue and also mark 👍 Helpful if you find my response worthy based on the impact.
Thanks
Ankur

[asifnoor]

Hi Irfan,

Glad you got the solution. Kindly note that this code has chances of giving duplicates, where as the code that i gave you will always return unique elements. Just check once.