Javascript- to randomize an array of functions

Question

This is a javascript code. I have a collection of 10 functions card11() to card25(). On-click in another HTML code, I want one of these functions to be called randomly. I applied the following logic, but it seems to be flawed. HELP, please!

 arr=[card11(), card12(), card13(), card14(), card15(), card21(), card22(), card23() , card24(), card25()];
    function myFunc(arr)
    {
      var d, c, b = arr.length;
      while (b)
      {
          c = Math.floor(Math.random() * b);
          d = arr[--b];
          arr[b] = arr[c];
          arr[c] = d;
      }
           return arr;
    }

I could be wrong, but those seem to be variations of the same function. Have you considered making a single more generic function with a parameter instead of the 10 you have now? — Tibos
– Tibos, Commented Jan 16, 2014 at 10:06
Umm I do not know how I can do that. The functions are pretty complex. — Prarthana Hegde
– Prarthana Hegde, Commented Jan 16, 2014 at 10:20
Perhaps you could post on CodeReview if you think the problem is interesting enough. Make sure the code is working first! — Tibos
– Tibos, Commented Jan 16, 2014 at 10:27

Kevin Bowersox · Accepted Answer · 2014-01-16 10:04:55Z

2

First, the array should contain references to the function instead of executing the function:

var arr=[card11, card12, card13, card14, card15, card21, card22, card23 , card24, card25];

Next, you can easily call a random function that array using this function:

function callRandom(arr){
    arr[Math.floor(Math.random() * arr.length)]();
}

Example Usage

function func1(){
    alert("func2");
}
function func2(){
    alert("func1");
}
function func3(){
    alert("func1");
}

var arr = [func1, func2, func3];


function callRandom(arr){
    arr[Math.floor(Math.random() * arr.length)]();
}

callRandom(arr);

JS Fiddle: http://jsfiddle.net/cqLLV/1/

answered Jan 16, 2014 at 10:04

Kevin Bowersox

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3 Comments

Prarthana Hegde Over a year ago

<td> <img src="card.jpg" id="a" onclick="myFunc(arr)"> </td> Would this be the right way to call it in HTML? I do not know what to pass as a parameter, since I am defining the array in the script file.

Kevin Bowersox Over a year ago

@user3193046 You should attach the event with addEventListener instead of inlining the handler.

Prarthana Hegde Over a year ago

No, I got it! I just declared the array locally inside the function and didnt pass any parameters. Its working fine now. Thank you!

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