title: R: selecting items matching criteria from a vector
body: <p>I have a numeric vector in R, which consists of both negative and positive numbers. I want to separate the numbers in the list based on sign (ignoring zero for now), into two seperate lists:</p>
  
  <ul>
  <li>a new vector containing only the negative numbers</li>
  <li>another vector containing only the positive numbers</li>
  </ul>
  
  <p>The documentation shows how to do this for selecting rows/columns/cells in a dataframe - but this dosen't work with vectors AFAICT.</p>
  
  <p>How can it be done (without a for loop)?</p>