Javascript Array Multidimensional Error

Question

I am trying to create a multidimensional array from a few lists I have in my VF controller. The Lists are correct, because when I output them just as individual tables, I get all the correct values. I am trying to load them into an array that looks likes this:

DataSet= [ [Name1, URL1, Login1, Created1],
           [Name2, URL2, Login2, Created2],
           [Name3, URL3, Login3, Created3],
           [Name4, URL4, Login4, Created4],
           .....
          ];

Here is how I am trying to construct the array. I am pushing all the List values into each of their own individual arrays, then looping them into the array in the order I wanted: Name(n), URL(u), Login(e), Created(c).

   <script>
 n = new Array();
     <apex:repeat value="{!names}" var="name">
       n.push('{!name}');
     </apex:repeat>


 u = new Array();
     <apex:repeat value="{!urls}" var="url">
       u.push('{!url}');
     </apex:repeat>

 e = new Array();
     <apex:repeat value="{!logins}" var="logs">
       e.push('{!logs}');
     </apex:repeat>


 c = new Array();
     <apex:repeat value="{!created}" var="create">
       c.push('{!create}');
     </apex:repeat>

var DataSet= new array(5000);

var i=0;
var j=0;

for(i;i<n.length;i++){ 
    for(j;j<3;j++){
        if(j=0) DataSet[i][j] = n[i];
        if(j=1) DataSet[i][j] = u[i];
        if(j=2) DataSet[i][j] = e[i];
        if(j=3) DataSet[i][j] = c[i];

   }
}
alert('test');
</script>

I tested all the arrays, they are display properly, I run into an issue on the looping. Let me know if there's something I did wrong.

Thanks in advanced.

Answer 1

First of all, I can't see why would you require nested loops at all. Your logic could have simply been written without the inner loop, being that you have determined number of separate lists:

for(i;i<n.length;i++){ 
    DataSet[i][0] = n[i];
    DataSet[i][1] = u[i];
    DataSet[i][2] = e[i];
    DataSet[i][3] = c[i];
}

However, this wouldn't have worked for you either, since in each iteration you would try to assign a value to the first element of the DataSet[i] object. Let's consider first iteration (i=0) - DataSet[0] is still undefined, as no value has been assigned to the element at that index yet. Accessing any property of that element (e.g. DataSet[0][0] = n[0];) would result in error:

TypeError: DataSet[i] is undefined
DataSet[i][0] = n[i];

What you could do is create temp array in each iteration, and assign it as a value to the current DataSet item, like so:

for(i;i<n.length;i++){ 
   var elm = [n[i], u[i], e[i], c[i]];
   DataSet[i] = elm;
}

This way you would get the multidimensional array you were looking for.