title: Subtracting many arrays
body: <p>I have one big array circa 50 values like this (for example I used smaller array):</p>
  
  <pre><code>    Array
  (
      [Adam Małysz] =&gt; 1
      [Justyna Kowalczyk] =&gt; 2
      [Janne Ahonen] =&gt; 3
      [Stefan Hula] =&gt; 4
      [Ole Einar Bjoerdalen] =&gt; 5
      [Jakub Janda] =&gt; 6
      [Mariusz Pudzianowski] =&gt; 7
      [Harry Potter] =&gt; 8
      [Vladimir Zografski] =&gt; 9
      [Pavel Karelin] =&gt; 10
      [Eddie Edwards] =&gt; 11
      [Apoloniusz Tajner] =&gt; 12
  )
  </code></pre>
  
  <p>and I have <em>n</em> smaller constant arrays with different values:</p>
  
  <pre><code>Array
  (
      [Adam Małysz] =&gt; 1
      [Janne Ahonen] =&gt; 2
      [Stefan Hula] =&gt; 3
      [Ole Einar Bjoerdalen] =&gt; 4
      [Vladimir Zografski] =&gt; 5
      [Pavel Karelin] =&gt; 6
      [Apoloniusz Tajner] =&gt; 7
      [Mariusz Pudzianowski] =&gt; 8
      [Jakub Janda] =&gt; 9
      [Harry Potter] =&gt; 10
  )
  Array
  (
      [Justyna Kowalczyk] =&gt; 1
      [Apoloniusz Tajner] =&gt; 2
      [Harry Potter] =&gt; 3
      [Janne Ahonen] =&gt; 4
      [Mariusz Pudzianowski] =&gt; 5
      [Adam Małysz] =&gt; 6
      [Jakub Janda] =&gt; 7
      [Ole Einar Bjoerdalen] =&gt; 8
      [Vladimir Zografski] =&gt; 9
      [Pavel Karelin] =&gt; 10
  )
  Array
  (
      [Adam Małysz] =&gt; 1
      [Janne Ahonen] =&gt; 2
      [Jakub Janda] =&gt; 3
      [Stefan Hula] =&gt; 4
      [Ole Einar Bjoerdalen] =&gt; 5
      [Justyna Kowalczyk] =&gt; 6
      [Harry Potter] =&gt; 7
      [Mariusz Pudzianowski] =&gt; 8
      [Vladimir Zografski] =&gt; 9
      [Apoloniusz Tajner] =&gt; 10
  )
  </code></pre>
  
  <p>So I want to subtract array values where is the same key like:</p>
  
  <blockquote>
    <p>Big Array: [Harry Potter] => 8<br>
                  [Mariusz Pudzianowski] => 7  </p>
    
    <p>Small Array #1: [Harry Potter] => 10<br>
                        [Mariusz Pudzianowski] => 8<br>
      Small Array #2: [Harry Potter] => 3<br>
                        [Mariusz Pudzianowski] => 5  </p>
    
    <p>Output: Difference between Small Array #1 and Big Array for key [Harry
    Potter] = 2<br>
            Difference between Small Array #1 and Big Array for key [Mariusz Pudzianowski] = 1   </p>
    
    <p>Output: Difference between Small Array #2
    and Big Array for key [Harry Potter] = 5<br>
            Difference between Small Array #2 and Big Array for key [Mariusz Pudzianowski] = 2</p>
  </blockquote>
  
  <p>Basically I'm stuck.
  Please help.</p>