title: Ruby- Adding/subtracting elements from one array with another array
body: <p>I do this:</p>
  
  <pre><code>a = [1,2,3,4]  
  b = [2,3,4,5]  
  c = b - a  
  put c 
  </code></pre>
  
  <p>I get this
  answer -> <code>[1]</code><br>
  I want this answer -> <code>[1,1,1,1]</code> (like matrix addition/subtraction)</p>
  
  <p>I tried this:</p>
  
  <pre><code>c.each {|e| c[e] = b[e] - a[e]}  
  </code></pre>
  
  <p>but I get this answer: <code>[1,0,0,0]</code>    </p>
  
  <p>Can someone give me a correct way to do this?  Thanks a lot!</p>