title: Percentage difference between different values in the same keys of two different arrays
body: <p>I'm looking for a solution to this problem.
  I got 2 arrays, like this:</p>
  
  <pre><code>    array(2) { 
         [20100526]=&gt;  array(1) { 
             ["ga:pageviews"]=&gt;  string(5) "19088" 
         } 
         [20100527]=&gt;  array(1) {
             ["ga:pageviews"]=&gt;  string(5) "15566" 
         } 
      } 
  
   array(2) { 
          [20100526]=&gt;  array(1) { 
              ["ga:pageviews"]=&gt;  string(5) "12043" 
          } 
          [20100527]=&gt;  array(1) {
              ["ga:pageviews"]=&gt;  string(5) "11953" 
          } 
      }
  </code></pre>
  
  <p>Now I'd like to create a new array, with the <strong>% difference</strong> between the values per key.</p>
  
  <p>Would be something like this:</p>
  
  <pre><code>array(2) { 
              [20100526]=&gt;  array(1) { 
                  ["ga:pageviews"]=&gt;  string(5) "88,23" 
              } 
              [20100527]=&gt;  array(1) {
                  ["ga:pageviews"]=&gt;  string(5) "74,54" 
              } 
          }
  </code></pre>
  
  <p>Can anyone help me how to create that array?</p>