String and Int Array Sorting

Question

I've got a problem sorting arrays. I'm currently trying to optimize a thing in a strategy game I play, and for that I need to calculate distance between all members of my alliance, the first towards the others and so on. No problem doing that actually. But now, what I want to do is sort the array of distance "ascending" and problem is, I need to write the corresponding nickname to match the distance. I've been searching for 2 days and I can't figure out a working solution.

I tried to copy the array before sorting it, but I need the unsorted array and with that sort function, it sorts the copy too ! Actually the code provided is good, speaking of distance accuracy but not sorted ascending. If I sort the distances, the nicknames are no longer corresponding. I don't know why they appear in the order of the pseudo_list because It's supposed to be sorted through nSort2() This is what I've ended up with so far :

//Sorting Distance[i] Array List
function nSort(arr) 
{
  return arr.sort((a, b) => a - b);
}

//Calculating Distance
function calcDist(xA, yA, xB, yB)
{
    return Math.sqrt(Math.pow((xB-xA), 2)+Math.pow((yB-yA), 2));
}

 //Here i'm trying to retrieved unsorted position of distance by index to sort the nicknames by their respective distances
function nSort2(arr_str, arr_nbr)
{
    var arr_nbr2 = arr_nbr.splice(0);
    var arr_sort = nSort(arr_nbr2);
    var str_sort = [];

    arr_str.forEach(function(element, i) 
    {
        j = arr_sort.indexOf(arr_nbr2[i], i);
        str_sort[i] = arr_str[j];
    });
    console.log(str_sort);
    return str_sort;
}

var pseudo_list = ["teddy95", "gabrielc", "ngozi"]; //The list (I just put the first 3 to not to write to much unnecessary code)
var x_ = [29, 26, 4]; // The X Coordinate list
var y_ = [519, 461, 143]; // The Y Coordinate list
var distance = [[]]; // The 2D Array for distance (distance[0][0] being the member's distance tower himself (which is obviously 0).

//Calculating Distances And Storing them in the 2D Array
y_.forEach(function(element, i) 
{
    distance[i] = [];
    x_.forEach(function(element, j) 
    {
        distance[i][j] = Math.ceil(calcDist(x_[i], y_[i], x_[j], y_[j]));
    });
});

//Displaying Sorted Array ascending (Trying)
y_.forEach(function(element, i) 
{
    x_.forEach(function(element, j) 
    {
            document.write(pseudo_list[i] + ' -> ' + nSort2(pseudo_list, distance[i])[j] + ': ' + distance[i][j] + '<br>');
    });
});

Maybe if you want to assign an member to distance, use a Map and then you can sort it by distance or by name? — Reddi, Jan 10 '19 at 13:42
I'm almost sure that your problem is based in a shallow copy of distance array, see this https://stackoverflow.com/questions/40433889/hard-copy-vs-shallow-copy-javascript — Emeeus, Jan 10 '19 at 16:20

score 2 · Accepted Answer · answered Jan 10 '19 at 14:12

I think your problem come from over complicating the data structures (I'm not insulting you just sharing an opinion).

In the code below all the input (pseudo, x, y) is stored in an object so player data is easier to manipulate. Then I'm not using a matrix because you end up creating new issues namely I'd expect distance[1][2] = distance[2][1] so sorting will create duplicate results (and the diagonal doesn't help since it represents the distance from yourself). Instead I have a 1D array constructed with no duplicates, i.e. it contains the distance from the first element to all the others (i.e. second, third, ...), then the second element from the "ones on the right" (i.e. third, fourth, ...), ... Once you have all the distance information, sorting is a trivial task so is displaying the result.

        //Calculating Distance
        function calcDist(xA, yA, xB, yB) {
            return Math.sqrt(Math.pow((xB - xA), 2) + Math.pow((yB - yA), 2));
        }

        let players = [{
            pseudo: "teddy95",
            x: 29,
            y: 519
        },
        {
            pseudo: "gabrielc",
            x: 26,
            y: 461
        },
        {
            pseudo: "ngozi",
            x: 4,
            y: 143
        }]

        let distances = []

        players.forEach(function (element, i) {
            for (let j = i + 1; j < players.length; ++j) {
                distances.push({
                    player1: element,
                    player2: players[j],
                    distance: Math.ceil(calcDist(element.x, element.y, players[j].x, players[j].y))
                })
            }
        })

        distances.sort(function (a, b) { return a.distance - b.distance })

        distances.forEach(function (element, i) {
            document.write(element.player1.pseudo + ' - ' + element.player2.pseudo + ' dist ' + element.distance + '<br>')
        })

String and Int Array Sorting

1 Answers1