title: is it possible if callback in array_filter receive parameter?
body: <p>I got this multiple array named <code>$files[]</code>, which consists of keys and values as below :</p>
  
  <pre><code>[0] =&gt; Array
  (
      [name] =&gt; index1.php
      [path] =&gt; http://localhost/php/gettingstarted/
      [number] =&gt; 1
  )
  
  [1] =&gt; Array
  (
      [name] =&gt; index10.php
      [path] =&gt; http://localhost/php/gettingstarted/
      [number] =&gt; 2
  )
  
  [2] =&gt; Array
  (
      [name] =&gt; index11.php
      [path] =&gt; http://localhost/php/gettingstarted/
      [number] =&gt; 3
  )
  </code></pre>
  
  <p>I use this code to create a new array consist of 'name' keys only. But it failed</p>
  
  <pre><code>array_filter($files, "is_inarr_key('name')");
  
  function is_inarr_key($array, $key)
  {
      //TODO : remove every array except those who got the same $key
  }
  </code></pre>
  
  <p>and I get this error:</p>
  
  <blockquote>
    <p>array_filter() [function.array-filter]: The second argument, 'is_inarr_key('name')', should be a valid callback in C:\xampp\htdocs\php\gettingstarted\index.php on line 15</p>
  </blockquote>
  
  <p>So my questions are:</p>
  
  <ol>
  <li>Is it possible to make the call-back function on <code>array_filter</code> receive parameter?</li>
  <li>What is the general rule of thumb on how to use callback in any PHP built-in function?</li>
  </ol>