title: Loc function in R?
body: <p>which(A &lt; B)</p>
  <p>Does anyone know which function (if any) will return the index of the
  true locations in a Boolean vector?
  For instance:</p>
  <pre><code>A=c(1,3,5,7,4);
  B=c(2,4,77,3,3);
  X=A&lt;B;
  So X is:X
  [1]  TRUE  TRUE  TRUE FALSE FALSE
  </code></pre>
  <p>I'd like to know if there is a function that will tell me the locations of where the TRUE values are?  for instance a vector that will list that the locations are at 1, 2, 3.  This function is sometimes called loc() in other languages.</p>