title: PHP: Check for duplicate values in a multidimensional array
body: <p>I have this issue with multidimensional arrays.</p>
  
  <p>Given the following multidimensional array:</p>
  
  <pre><code>Array(
  [0] =&gt; Array("a", "b", "c")
  [1] =&gt; Array("x", "y", "z")
  [2] =&gt; Array("a", "b", "c")
  [3] =&gt; Array("a", "b", "c")
  [4] =&gt; Array("a", "x", "z")
  )
  </code></pre>
  
  <p>I want to check its values and find duplicates (i.e. keys 0, 2 and 3) leaving just one key - value pair deleting the others, resulting in somthing like this:</p>
  
  <pre><code>Array(
      [0] =&gt; Array("a", "b", "c")
      [1] =&gt; Array("x", "y", "z")
      [2] =&gt; Array("a", "x", "z")
      )
  </code></pre>
  
  <p>How can I do that??</p>