title: How to access the slots of an S4 object in R
body: <p>I'm working with wavelets on a program and I'm used the package <code>wavelets</code> to create the DWT of a time series using the function <code>dwt</code>. This function returns an object of class <code>dwt</code>, which is a S4 object with many slots: <code>W</code>, <code>V</code>, <code>levels</code>, <code>filter</code>, and so on.</p>
  
  <p>How can I access the <code>W</code>'s as a vector?</p>