title: Append an Array to an Array of Arrays in PowerShell
body: <p>I'm trying to build up a multi-dimensional array in PowerShell programmatically using CSV files located on disk.  I have been importing the array into a temporary variable and then appending the array to the array.  Instead of an array of arrays I get a single array with the total number of rows.  I worked it out with smaller arrays and found the following:</p>
  
  <pre><code>$array1 = "11","12","13"
  $array2 = "21","22","23"
  $array3 = "31","32","33"
  
  $arrayAll = $array1, $array2, $array3
  $arrayAll.Count # returns 3
  
  $arrayAll = @();
  $arrayAll += $array1
  $arrayAll += $array2
  $arrayAll += $array3
  
  $arrayAll.count # returns 9
  </code></pre>
  
  <p>The first method for building the array works but I need to be able to use the second method.  How do I fix this?</p>