title: array concatenation in F#
body: <p>Are there any analogs to Matlab's <a href="http://www.mathworks.com/help/matlab/ref/horzcat.html" rel="nofollow noreferrer">horzcat</a>() and <a href="http://www.mathworks.com/help/matlab/ref/vertcat.html" rel="nofollow noreferrer">vertcat</a>() functions in F#? Because what I'm doing now seems asinine. There is a related question <a href="https://stackoverflow.com/questions/2367733/f-how-to-append-join-array2d-and-combine-1d-arrays-to-array2d">here</a> but it seems pretty dated.</p>
  
  <pre><code>    let arr = Array.init 5 (fun i -&gt; 1.)
      let xMat = DenseMatrix.init l 2 (fun r c -&gt; if c = 0 then 1. else arr.[r])
  </code></pre>
  
  <p>There is an Array.concat but it seems to work only vertically.</p>