Question

I am trying to sort my locations array from shortest to longest distance with the following code:

for(var i=0; i<locations.length;i++)
{
    var swapped = false;
    for(var j=locations.length; j>i+1;j--)
    { 
        if (locations[j]['distance'] < locations[j-1]['distance'])
        {
            var temp = locations[j-1];
            locations[j-1]=locations[j];
            locations[j]=temp;
            swapped = true;
        }
    }
    if(!swapped)
        break;
}

When I tried running the program, I get the following error in Firebug:

locations[j] is undefined

I console.logged the locations array and this is what it lloks like:

[Object { id="1", marker=U, more...}, Object { id="4", marker=U, more...}, Object { id="6", marker=U, more...}, Object { id="3", marker=U, more...}, Object { id="2", marker=U, more...}, Object { id="5", marker=U, more...}]

Is there a way to numerically index the objects, while keeping the objects’ data associatively indexed?

Or is there a way to access the ith+1 or ith-1 element if I have for resort to using this.distance in a foreach loop?

Answer 1

You started 1 to late, remember array keys are indexes, which start at 0

for(var j=locations.length-1; j>i+1;j--)
{ 
   console.log(j);
  if (locations[j-1]['distance'] && locations[j]['distance'] < locations[j-1]['distance'])
    {
        var temp = locations[j-1];
        locations[j-1]=locations[j];
        locations[j]=temp;
        swapped = true;
    }
}

You’re going to run into a problem on the last loop so I added if(locations[j-1]['distance'] ...