title: Transform a 3D array into a matrix in R
body: <p>I'm trying to transform a 3D array into a matrix. I want the third dimension of the array to form the first row in the matrix, and this third dimension should be read by row (i.e., row 1, then row 2 etc... of dimension 3 should make up the first row of the matrix). I've given an example below, where the array has dimensions of 4, 3, and 5, and the resulting matrix has 5 rows and 12 columns. I have a solution below that achieves what I want, but it seems very cumbersome for large arrays (it first creates vectors from the elements of the array (by row), and then rbinds these to form the matrix). Is there a more elegant way to do this? Thanks in advance for any suggestions.</p>
  
  <pre><code>dat &lt;- array( rnorm(60), dim=c(4, 3, 5) )   
  
  results &lt;- list(1:5)            
  for (i in 1:5) {  
      vec &lt;- c( t(dat[, , i]) )  
      results[[i]] &lt;- vec  
      }
  
  datNew &lt;- rbind( results[[1]], results[[2]], results[[3]], results[[4]], results[[5]] )  
  </code></pre>