Special sort on an array of objects

[roele]

Hi,

i'm working on a game where i need a special sort algorithm which i can't figure out.... I save the players into an array in form of an object. This containts the player data and his entered values. The player should guess how many medals a country will get a the olympic games... Then the object contains a field with the difference to the final value too.

player = [
{Name:"", Prename:"", Gold:9, DifGold:1, Silver:19, DifSilver:0, Bronze:15,
DifBronze:-3}
];

The problem now is to sort this array on the three fields DifGold, DifSilver and
DivBronze. I used an Array protoype from Keneth Bunch for sorting on 2 fields.
Works all well till now...(ok just with 2 fields but who cares). BUT if a player guessed less Gold than they really got it is ranked better than one who has guessed the right number! Of course -1 < 0 is mathematically correct but i need to rank all number less than 0 after all other positive values.

Any ideas how to solve this ... ?

Kind regards,
Roland Schaer

[roele]

The script i use so far looks like:

Array.prototype.sortOn = function(p) {
    Array.$sortprop = p;
    var sortfunc = function (a,b) {
      var p = Array.$sortprop;
	  return b[p] < a[p]; 
    }
                             
    this.sort(sortfunc);
    delete Array.$sortprop;
}
Array.prototype.subSort = function(sMainKey, sSubKey){
	
	// declare data holders
	var copy = this.slice(0);
	var holder = new Object();
	var returned = new Array();

	
	// sort array on sMainKey
	copy.sortOn(sMainKey);
	
	// create seperate arrays to hold values sorted on sMainKey
	var i = this.length;
	while(i--){
		// field of obj doesnt exist add it
		if(holder[copy[i][sMainKey]] == undefined){ 
			holder[copy[i][sMainKey]] = new Array();
			holder[copy[i][sMainKey]].push(copy[i]);
		}
		// else add fields into it
		else{
			holder[copy[i][sMainKey]].push(copy[i]);
		}
	}

	// subsort the subarrays on sSubKey
	for (prop in holder){
		holder[prop].sortOn([sSubKey]);
	}
	
	// add all values into one array 
	for (prop in holder){
		returned = returned.concat(holder[prop]);
	}
	
	// return subsorted array
	return returned;
};

[littleRichard]

There are some problems with your code. you don't need to do anything complicated like overwrite sortOn.

What you need to do is use sort with a sortFuntion. I can't write specific code for you at the moment but here is an example of some code I wrote last week sorting on multiple fields.

It will group together objects with the same y value and then whithin those groups it will sort on x1.

someData = 
[
    {x1:43,  y:205},
    {x1:-9,  y:225},
    {x1:225, y:225},
    {x1:36,  y:245},
    {x1:-9,  y:265},
    {x1:44,  y:285},
    {x1:165, y:285},
    {x1:118, y:305},
    {x1:-9,  y:285}
];

someData.sort(this.mySort);

function mySort(a, b)
{
    ay = a.y;
    ax = a.x1;
    by = b.y;
    bx = b.x1;
    
    if(ay < by)
    {
        return -1;
    }
    else if(ay > by)
    {
        return 1;
    }
    else
    {
        if(ax < bx)
        {
            return -1;
        }
        else if(ax > bx)
        {
            return 1;
        }
        else
        {
            return 0;
        }
    }
}

The code that matters is what's inside the mySort function.

1) if you want 'a' to show up before 'b' then return -1
2) if you want 'a' to show up after 'b' then return 1
3) and if 'a' and 'b' are the same return 0

I'd recomend reading up on Array.sort in the as dictionary. It gives a pretty good explanation.

Cheers,
Rich