question about random numbers

Ad Mulders · **Posted:** February 10th, 2009, 2:20 pm

How can i tell the random function to skip numbers that already been taken.

Kind regards,

Ad

mackavi · **Posted:** February 10th, 2009, 2:26 pm

You can't.

Depending on what your doing it's probably best to call a number from a depleting randomised pool.

This can be achieved by populating an array with your number set and randomising the array. Then you simply work through each element in order.

The function to randomise the array has been posted several times on the forum.

Mack

Ad Mulders · **Posted:** February 10th, 2009, 2:45 pm

Hi Macavi,

I found another way to do it.
On the first page i put all the numbers.
After picking a random number let's say number 6 i go to the next page and tell the button to pick random over only 5 numbers etc.
I am working on it right now. Keep you informed.

Ad

lmc · **Posted:** February 21st, 2009, 6:10 pm

I have used this for creating a random order of non repeating, works very well. If you have numberFeatures of say 5, it will randomly create an array of number of 0 - 5, non repeating and then use this as your list.

Code:

function createArray()
{
   for (var i = 0; i < numberFeatures; i++) 
   {
   randomFeatureQuestion[i] = i;
   Debug.trace(randomFeatureQuestion[i] + "\n");
   }
      
fisherYates(randomFeatureQuestion);
Debug.trace("randomFeatureQuestion " + randomFeatureQuestion + "\n");
}


function fisherYates(myArray) 
{
var i = myArray.length;
if ( i == 0 ) return false;

   while ( --i )
   {
   var j = Math.floor( Math.random() * ( i + 1 ) );
   var tempi = myArray[i];
   var tempj = myArray[j];
   myArray[i] = tempj;
   myArray[j] = tempi;
   }
}

Ad Mulders · **Posted:** February 21st, 2009, 8:49 pm

Well the option i suggested didn't work so let's try your script Imc

Ad

lmc · **Posted:** February 22nd, 2009, 2:00 pm

How I normally work random questions non-repeating it.

I read the questions into an array featureArray[], then I use the code above to create a random sequence of another array randomFeatureQuestion[] based on the number of features in featureArray[].

I then use the following to call each question:

Code:

var QuestionNo = randomFeatureQuestion[nextQuestion];
Question = featureArray[QuestionNo];
nextQuestion = nextQuestion + 1;

This should work above, it's nice and simple to implement. Out put example from everything would be.

Say you have 5 questions, the randomFeatureQuestion[] would be populated with a random sequence of numbers up to 5 (as array counted from 0). So the sequence could be 4,0,1,3,2. This sequence is then used to call the array number in the featureArray[].

marian hausman · **Posted:** February 22nd, 2009, 8:42 pm

Oops, thats iteresting, but too difficult for me. Do you have an example .imp so i can analyse it and implement it in a small game i am working on.

Marian

Digital Workshop

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