title: find highest value in associative array
body: <p>I've got an array which looks like this:</p>
  
  <pre><code>array(10) {
    [0]=&gt;
    array(4) {
      [0]=&gt;
      array(5) {
      ...
      }
      [1]=&gt;
      array(5) {
      ...
      }
      [2]=&gt;
      array(5) {
      ...
      }
      ["opt"]=&gt;
      float(0.5)
    }
    [1]=&gt;
    array(4) {
      [0]=&gt;
      array(5) {
      ...
      }
      [1]=&gt;
      array(5) {
      ...
      }
      [2]=&gt;
      array(5) {
      ...
      }
      ["opt"]=&gt;
      float(1)
    }
    .....
  }
  </code></pre>
  
  <p>I want to find out the Key of the Array of the first layer, which has the highest value at the key 'opt'. I hope you got what i mean. 
  Sorry for that sentence, but it was kind of hard to explain! ;) </p>
  
  <p>EDIT:
  What I've thought of was the use of max() creating all the entries with the use of foreach. I wasnt sure if this would be the best way.  </p>