Randomizing a bank of numbers

[Odisey]

Hello,
Can someone help me figure this math. I have a bank of numbers. I have:

Twelve 1's
Twelve 2's
Twelve 3's
Twelve 4's
Twelve 5's
Twelve 6's
Twelve 7's
Twelve 8's

I want to randomly generate 3 digit numbers with the bank until the bank is empty. One limitation is none of the three digit numbers can have the same numbr in it twice .... like 223. And another is the same three digit number cannot be repeated, such as 345, 345.

Thank you,
Odisey

[moagrius]

Array.prototoype.contains = function(element){
    var count = this.length;
    while(count){
        if(this[--count]==element){
            return true;
        };
    };
    return false;
};
function getrandomindex(array){
    return Math.round(Math.random()*(array.length-1));
};
function getrandomelement(array){
    return array[Math.round(Math.random()*(array.length-1))];
};

var bank = [];
for(var i=1;i<9;i++){
    for(var j=0;j<12;j++){
        bank.push(i);
    };
};
trace(bank);

var returns = [];

function gettrips(){
    if(bank.length < 3){
        return false;
    };
    var a = getrandomindex(bank);
    var b = getrandomindex(bank);
    while(bank[a]==bank[b]){
        b = getrandomindex(bank);
    }
    var c = getrandomindex(bank);
    while(bank[b]==bank[c] || bank[a]==bank[c]){
        c = getrandomindex(bank);
    };
    var d = [bank[a],bank[b],bank[c]].join("");
    
    if(returns.contains(d)){
        return gettrips();
    };
    
    bank.splice(a,1);
    bank.splice(b,1);
    bank.splice(c,1);
    
    returns.push(d);
    return d;
        
};

this.onMouseDown = function(){
    gettrips();
    trace(returns);
    trace(bank.length);
}; 

[widged]

Here is a reusable function I tend to use for random sort with no repetition. This will sort any array in random order, with each item appearing once. What it does is swap a element picked at random with the last element of the array. The 'pickable' set will be reduced by 1, swap, etc.

arrRnd = randomSort(arr)

/**
  randomSort, no repetition
*/
function randomSort(itms) {
    var oItem:Object = new Object()
    var lastPos:Number = itms.length

    for(var i = 0; i<itms.length; i++){
      lastPos = itms.length-i-1
      rnd = Math.floor(Math.random() * (lastPos))
      oItem = itms[lastPos]
      itms[lastPos] = itms[rnd]
      itms[rnd] = oItem;
    }
    return itms;
} 

[Odisey]

Array.prototoype.contains = function(element){
    var count = this.length;
    while(count){
        if(this[--count]==element){
            return true;
        };
    };
    return false;
};
function getrandomindex(array){
    return Math.round(Math.random()*(array.length-1));
};
function getrandomelement(array){
    return array[Math.round(Math.random()*(array.length-1))];
};

var bank = [];
for(var i=1;i<9;i++){
    for(var j=0;j<12;j++){
        bank.push(i);
    };
};
trace(bank);

var returns = [];

function gettrips(){
    if(bank.length < 3){
        return false;
    };
    var a = getrandomindex(bank);
    var b = getrandomindex(bank);
    while(bank[a]==bank[b]){
        b = getrandomindex(bank);
    }
    var c = getrandomindex(bank);
    while(bank[b]==bank[c] || bank[a]==bank[c]){
        c = getrandomindex(bank);
    };
    var d = [bank[a],bank[b],bank[c]].join("");
    
    if(returns.contains(d)){
        return gettrips();
    };
    
    bank.splice(a,1);
    bank.splice(b,1);
    bank.splice(c,1);
    
    returns.push(d);
    return d;
        
};

this.onMouseDown = function(){
    gettrips();
    trace(returns);
    trace(bank.length);
}; 

This is good... but ,,, here is the output:

1,1,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,2,2,3, 3,3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,5,5, 5,5,5,5,5,5,5,5,5,5,6,6,6,6,6,6,6,6,6,6,6,6,7,7,7, 7,7,7,7,7,7,7,7,7,8,8,8,8,8,8,8,8,8,8,8,8

[Odisey]

Here is a reusable function I tend to use for random sort with no repetition. This will sort any array in random order, with each item appearing once. What it does is swap a element picked at random with the last element of the array. The 'pickable' set will be reduced by 1, swap, etc.

arrRnd = randomSort(arr)

/**
  randomSort, no repetition
*/
function randomSort(itms) {
    var oItem:Object = new Object()
    var lastPos:Number = itms.length

    for(var i = 0; i<itms.length; i++){
      lastPos = itms.length-i-1
      rnd = Math.floor(Math.random() * (lastPos))
      oItem = itms[lastPos]
      itms[lastPos] = itms[rnd]
      itms[rnd] = oItem;
    }
    return itms;
} 

Maybe I can use this somehow.... Thank you

[moagrius]

odisey - that's just the output of the bank of numbers. run that, then mouse down several times and you'll see it returning what you asked for.

[moagrius]

maybe this example will be easier to understand. just open a new FLA, paste in frame 1's actions panel, and test movie.

Array.prototoype.contains = function(element){ 
    var count = this.length; 
    while(count){ 
        if(this[--count]==element){ 
            return true; 
        }; 
    }; 
    return false; 
}; 
function getrandomindex(array){ 
    return Math.round(Math.random()*(array.length-1)); 
}; 

var bank = []; 
var returns = [];

for(var i=1;i<9;i++){ 
    for(var j=0;j<12;j++){ 
        bank.push(i); 
    }; 
}; 

function gettrips(){ 
    if(bank.length < 3){ 
        return false; 
    }; 
    var a = getrandomindex(bank); 
    var b = getrandomindex(bank); 
    while(bank[a]==bank[b]){ 
        b = getrandomindex(bank); 
    } 
    var c = getrandomindex(bank); 
    while(bank[b]==bank[c] || bank[a]==bank[c]){ 
        c = getrandomindex(bank); 
    }; 
    var d = [bank[a],bank[b],bank[c]].join(""); 
     
    if(returns.contains(d)){ 
        return gettrips(); 
    }; 
     
    bank.splice(a,1); 
    bank.splice(b,1); 
    bank.splice(c,1); 
     
    return d; 
         
}; 

trace(gettrips());
trace(gettrips());
trace(gettrips());
trace(gettrips());
trace(gettrips());
trace(gettrips());
trace(gettrips());
trace(gettrips());
trace(gettrips());
trace(gettrips()); 

[widged]

Maybe I can use this somehow....

If you are after creating a bank of 12 times the values 1-8, before the function, try something like this.

// build an array with 12 times the values 1-8
var arrVal:Array = new Array()
for (i = 1; i <= 8; i++) {
    for (j = 0; j < 12; j++) {
        arrVal.push( i)
    }
}

// sort the array in random order, no repetition
arrRnd = randomSort(arrVal) // use the function given in the previous post

// optional, a pretty output
commaSep = arrayCombine(arrRnd, ',')
trace(commaSep)

/**
  arrayCombine
*/
function arrayCombine(arr, sep) {
  var str:String = ''
  for (i = 0; i < arr.length; i++) {
    str += arr[i] + sep
  }
  str = str.substr(0, str.length - sep.length) // removes trailing separator
                                              // faster than an if in the loop
  return str
} 

[widged]

Note however that it doesn't get you any close from solving your problem of avoiding '223'.

You can try and add conditions like the one below...

// sort the array in random order, no repetition
arrRnd = randomSort(arrVal) // use the function given in the previous post
var arrTriplet:Array = new Array()
for (var i = 0; i < arrRnd.length; i++) {
    digit = arrRnd[i]
    if(arrTriplet[0] != undefined && digit == arrTriplet[0]) { next }
    if(arrTriplet[1] != undefined && digit == arrTriplet[1]) { next }
    arrTriplet.push(digit)
    if(arrTriplet.length == 3) { break }
}
triplet = arrayCombine(arrTriplet, '')
trace (triplet) 

but the script above doesn't check that you don't pick the same number twice (345, 345). With a bank approach, you will come across one problem after another.

Well, the thing is that you really don't need to start from 12 times 1-8 to get all possible combinations of 3 digits made of numbers from 1-8 ;-). The bank is somewhat irrelevant. Especially if each number occurs with the same probability (12 count). You are better off using permutations.

var arrTriplets:Array = new Array()
for (i = 1; i <= 8; i++) {
    for (j = 1; j <= 8; j++) {
        for (k = 1; k <= 8; k++) {
            if(i != j && j != k && k != i ) {
                arrTriplets.push("" + i + "" +  j  + "" +  k)
            }
        }
    }
}

arrRnd = randomSort(arrTriplets)
commaSep = arrayCombine(arrRnd, ',')
trace(commaSep) 

(see posts above for functions randomSort and arrayCombine).

[moagrius]

widged: how is arrayCombine any different than join? just curious...

[widged]

widged: how is arrayCombine any different than join? just curious...

I have been coding with PHP for the last month (before you ask, join also exists in php but as an alias of implode)... I couldn't remember the magic word and I had no book at hand at the time I replied. I ran a rapid search on the web and wasn't successful, so I bundled a function of my own :-)

Yup, always use native functions when available.