title: Compute means across a list on R
body: <p>I have a list with the following structure: </p>
  
  <pre><code>&gt; str(test)
  List of 5
  $ :List of 2
  ..$ : num [1:4] 0.0544 0.0839 0.0486 0.043
  ..$ : num [1:4] 0.0799 0.2434 0.0373 0.2166
  $ :List of 2
  ..$ : num [1:6] 0.938 1.047 1.022 0.689 0.39 ...
  ..$ : num [1:6] 0.871 0.25 0.824 0.664 0.481 ...
  $ :List of 2
  ..$ : num [1:4] 0.000598 0.000923 0.000535 0.000473
  ..$ : num [1:4] 0.001039 0.003164 0.000485 0.002816
  $ :List of 2
  ..$ : num [1:6] 0.01032 0.01152 0.01124 0.00758 0.00429 ...
  ..$ : num [1:6] 0.01133 0.00325 0.01071 0.00864 0.00625 ...
  $ :List of 2
  ..$ : num -0.659
  ..$ : num -0.962
  </code></pre>
  
  <p>I want to compute the mean of each entry, i.e. for the first entry I want:</p>
  
  <pre><code>x &lt;- mean(c(0.0544, 0.0839, 0.0486, 0.043))
  y &lt;- mean(c(0.0799, 0.2434, 0.0373, 0.2166)) 
  </code></pre>
  
  <p>And finally the mean of those two results = mean(c(x,y).</p>
  
  <p>What is the most efficient way to do this?</p>