Using a dynamic variable within a for statement

Question

I would like to dynamically create and reference some variables on the fly, but i'm not understanding how to.

Here is what I would think 'should' work, but I know doesn't.

var weeks = 4;
 for(i=0; i<weeks.length;i++){
  var 'week_'+i = valueFromXML;
}



function wtFn (){
  'week_'+i.splice(-1, 1);
  if('week_'+i.length <=0){
    $(this).parent().parent().slideUp();
  }
}

I'm open to suggestions. Thanks in advance.

Answer 1

You can't declare variables dynamically it without using eval, and that is not considered as a good practice.

I would recommend you to use an object to store your values as properties:

var weeks = 4;
var obj = {};
for(var i = 0; i< weeks; i++){
  obj['week_'+i] = valueFromXML;
}

Then you can access the properties like:

alert(obj['week_'+i]);

Answer 2

You want to use arrays.

var weeks = new Array();

for(i=0; i < weeks.length;i++) {
  weeks[i] = valueFromXML;
}

Answer 3

As noted by others, arrays or objects are the way to go. But if you really must, you can sort of create dynamic variables -- or rather you create members of the global object, window. Assuming this is executing in a browser, do this:

var weeks = 4;
 for(i=0; i<weeks.length;i++){
  var window['week_'+i] = valueFromXML;
}



function wtFn (){

  window['week_'+i].splice(-1, 1);
  if(window['week_'+i].length <=0){
    $(this).parent().parent().slideUp();
  }
}

This works because in a browser, window['xyz'] will return the same object as xyz (that's assuming xyz wasn't created inside a function using the keyword var).