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up vote 3 down vote favorite

Is there a function in javascript to do this - test if a given value (a string in my case) exists in an array (of strings)? I know I could just loop over each value, but I'm wondering if js has a shorthand for this.

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possible duplicate of Javascript - array.contains(obj) – annakata Oct 1 '10 at 13:07
Indexed arrays may not be the correct data structure if you need to do this frequently. Consider using an associative array / object representation (which affords you the logical in operator). – annakata Oct 1 '10 at 13:09

3 Answers

up vote 3 down vote accepted

jquery has .inArray() method. It's the best I know..

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1  
this would work, I'm using jquery. thanks – bba Oct 1 '10 at 13:01
@bba, you might want to add information like that to your question. And to the tags for your question. (Edited your question to add the 'jquery' tag.) – David Thomas Oct 1 '10 at 13:03
@bba - Be sure to tag your question with jQuery if that's the case, it will get very different answers in many cases. :) – Nick Craver♦ Oct 1 '10 at 13:03
Ill be sure to keep that in mind. thanks – bba Oct 1 '10 at 13:04
up vote 2 down vote

There's .indexOf() for this, but IE<9 doesn't support it:

if(array.indexOf("mystring") > -1) {
  //found
}

From the same MDC documentation page, here's what to include (before using) to make IE work as well:

if (!Array.prototype.indexOf)
{
  Array.prototype.indexOf = function(elt /*, from*/)
  {
    var len = this.length >>> 0;

    var from = Number(arguments[1]) || 0;
    from = (from < 0)
         ? Math.ceil(from)
         : Math.floor(from);
    if (from < 0)
      from += len;

    for (; from < len; from++)
    {
      if (from in this &&
          this[from] === elt)
        return from;
    }
    return -1;
  };
}

.indexOf() returns the index in the array the string was found at, or -1 if it wasn't found.

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up vote 0 down vote

For functions that are in php and should be in javascript or I haven't found yet I go to: http://phpjs.org

The function you want use if you're just using javascript is in_array here: http://phpjs.org/functions/in_array:432

Otherwise, use the jQuery solution on this page.

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