title: powershell compare two arrays, create third array with only nonmatching values
body: <p>Firstly the only thing I have available is powershell.
  I have figured out how to compare two arrays; however, I am having a bit if difficulty figuring out how to get the data back in the format I need.</p>
  
  <pre><code>$foo = @(100, 200 ,300 ,400 ,500 ,600 ,700 ,800 ,900 ,1000)
  $bar = @(50, 100, 600 , 900)
  </code></pre>
  
  <p>Desired results would be an array with the following information</p>
  
  <pre><code> 50, 200, 300, 400, 500, 700, 800, 1000
  </code></pre>
  
  <p>Note that the like values </p>
  
  <pre><code>100, 600 , 900
  </code></pre>
  
  <p>are dropped and </p>
  
  <pre><code>50 
  </code></pre>
  
  <p>which is in the second array is added to the output.</p>
  
  <p>is this possible?</p>
  
  <p>thanks</p>