title: grep + arrays + index
body: <p>First sorry for the title but i dont realy know how to explain, i'm not experimented and it's probably realy simple to solve...</p>
  
  <p>So i got two arrays:</p>
  
  <pre><code>AR1=(c a b c c d)
  AR2=(z y x w v u)
  </code></pre>
  
  <p>I have to grep thing in <code>AR1</code> for make an <code>AR3</code> (this part is ok) but How can i do for have or <code>AR4</code> or <code>AR4bis</code></p>
  
  <pre><code>AR3=(c c c d)
  </code></pre>
  
  <p>what i'm looking for:</p>
  
  <pre><code>AR4=(z w v u)
  AR4bis=(0 3 4 5)
  </code></pre>
  
  <p>thx..</p>