Variable declaring within function - looping

Question

I've got problems with my variables when i'm doing a function. This is just a silly example. In my code I've got a lot of variables I want to use in the function so I don't have to write function over and over again for each variable "ex1, ex2 etc.." Below here is what I want to do really simple. First check for "ex1" where it equals the declared value, then perform action (animation in real code). Then do the same for "ex2" and so on. Is there a simple way to do this?

<script>
var ex1 = 'frog'; //Those are not set manually. ID's in real code
var ex2 = 'pig';
var ex3 = 'horse';
var ex4 = 'bird';

var x = 0;
setInterval("call", 5000);
function call(){

    x++;

    if(('ex' + x) == 'frog'){
    //action a
    }
    else if(('ex' + x) == 'pig'){
    //action b
    }
    else if(('ex' + x) == 'horse'){
    //action c 
    }
    else if(('ex' + x) == 'bird'){
    //action d
    }

}

</script>

window['ex'+x]. There should be a duplicate.

Zeta
– Zeta

2013-10-23 08:37:58 +00:00
Commented Oct 23, 2013 at 8:37 — Zeta
– Zeta, Commented Oct 23, 2013 at 8:37
like if(window['ex' + x] == y) ? @Zeta

PeterP
– PeterP

2013-10-23 08:39:41 +00:00
Commented Oct 23, 2013 at 8:39 — PeterP
– PeterP, Commented Oct 23, 2013 at 8:39
I think making ex.. an array will make it easier.

MC ND
– MC ND

2013-10-23 08:40:07 +00:00
Commented Oct 23, 2013 at 8:40 — MC ND
– MC ND, Commented Oct 23, 2013 at 8:40
Yes, window holds all global variables.

Zeta
– Zeta

2013-10-23 08:40:15 +00:00
Commented Oct 23, 2013 at 8:40 — Zeta
– Zeta, Commented Oct 23, 2013 at 8:40

rink.attendant.6 · Accepted Answer · 2013-10-23 08:47:33Z

Global variables are properties of the window object (in a browser anyways). You can access properties using square bracket notation like this:

var ex1 = 'frog'; //Those are not set manually. ID's in real code
var ex2 = 'pig';
var ex3 = 'horse';
var ex4 = 'bird';

var x = 0;

function call(){

    x++;

    if(window['ex' + x] === 'frog'){
    //action a
    }
    else if(window['ex' + x] === 'pig'){
    //action b
    }
    else if(window['ex' + x] === 'horse'){
    //action c 
    }
    else if(window['ex' + x] === 'bird'){
    //action d
    }

}

setInterval(call, 5000);

However, making ex an array would probably be better here:

var ex = [];
ex[1] = 'frog'; //Those are not set manually. ID's in real code
ex[2] = 'pig';
ex[3] = 'horse';
ex[4] = 'bird';

var x = 0;

function call(){

    x++;

    if(ex[x] === 'frog'){
    //action a
    }
    else if(ex[x] === 'pig'){
    //action b
    }
    else if(ex[x] === 'horse'){
    //action c 
    }
    else if(ex[x] === 'bird'){
    //action d
    }

}

setInterval(call, 5000);

If you're doing this for a lot of strings, use a switch statement:

var ex = [];
ex[1] = 'frog'; //Those are not set manually. ID's in real code
ex[2] = 'pig';
ex[3] = 'horse';
ex[4] = 'bird';

var x = 0;

function call(){

    x++;
    switch(ex[x]) {
       case 'frog':
           //action a
           break;
       case 'pig':
           //action b
           break;
       case 'horse':
           //action c
           break;
       case 'bird':
           //action d
           break;
    }

}

setInterval(call, 5000);

pax162 · Accepted Answer · 2013-10-23 08:43:39Z

1

Also, regarding the ifs, a more elegant approach would be to have an object containing all the actions, like this:

var actions = {
  frog:function(){
  //action a
  },
  pig:function(){
    //action b
  }
}

and then just find the action in the object and call it if found

var action = actions['ex' + x]
if (action) {
  action();
}

answered Oct 23, 2013 at 8:43

pax162

4,7452 gold badges25 silver badges30 bronze badges

Collectives™ on Stack Overflow

Variable declaring within function - looping

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related