How do I match ANY element of an array?

Question

How do I check if a variable is equal to any element of an array?

var myButton = document.getElementById("myButton");
var myVar; //myVar value is set to "One", "Two" or "Three" sometime later

myArray = ["One","Two","Three"];

myButton.onclick = function () {
    if (myVar === myArray) {
        alert ("it's a match!");
    } else {
                alert ("it's not a match!");
        }
};

The simplest and most efficient is to loop. If you want something fancy look at http://stackoverflow.com/questions/890782/javascript-function-inarray — Denys Séguret, Nov 28 '12 at 18:20
You have to loop, but you can `break;` on the first match so you don' tneed to continue looping. — Michael Berkowski, Nov 28 '12 at 18:21

score 1 · Answer 1 · answered Nov 28 '12 at 18:19

1

You have to loop through myArray and check each element.

However, you can use indexOf if you don't care about IE 8 or earlier.

answered Nov 28 '12 at 18:19

Daniel A. White

187,200
47
362
445

Forgive me, I'm new to javascript, but when I hear people say that I normally see them do something like: `var myArrayLength = myArray.length;` but from what I can tell that only makes myArrayLength = 3. I guess I don't know what to do with that. – badmidget Nov 28 '12 at 18:23
2

@user1860777 I don't understand how this relates to the question or this answer. – phant0m Nov 28 '12 at 18:29
As I said, I'm new to javascript so I appreciate the info you provided. For now, I did it the oldschool way described by Bruno, but I'm happy to now know about indexOf. I'm sure I'll be using it soon. – badmidget Nov 29 '12 at 15:34

Bruno · Accepted Answer · 2012-11-28T20:30:57.383

1

This should do it

myButton.onclick = function () {
    var i = myArray.length;
    while( i-- ) {
        if( myVar === myArray[i] ) {
            alert("it's a match");
            return;
        }
    }
    alert("it's not a match");
}

edited Nov 28 '12 at 20:30

answered Nov 28 '12 at 18:25

Bruno

5,772
1
26
43

thanks for this! it's going to exit the while loop when i=0? – Alex Gordon Nov 28 '12 at 18:39
You reinventing indexOf() ? – epascarello Nov 28 '12 at 18:53
Not really. If every browser supported it I would change my answer. – Bruno Nov 28 '12 at 18:55
I'm trying to implement this solution. I don't quite have it yet. I mocked it up here: [http://jsfiddle.net/Y7wAY – badmidget Nov 28 '12 at 20:26
Sorry, I had an error in my function but it is corrected now. Here is the [fiddle](http://jsfiddle.net/Y7wAY/1/) – Bruno Nov 28 '12 at 20:34
I did finally get this working! Thanks so much for you help! :) I may have figured it out earlier but I had an issue where my global variable wasn't being recognized within the function. Once I moved the variable into the function, it started working. Thanks again! – badmidget Nov 29 '12 at 15:29
@user1860777 Glad you got there :) – Bruno Nov 29 '12 at 15:33

How do I match ANY element of an array?

2 Answers2