title: R list of lists to data.frame
body: <p>I've got a list of lists, call it <code>listHolder</code>, which has length 5. </p>
  
  <p>Every element in <code>listHolder</code> is a list of numeric data, with 160 or so elements.</p>
  
  <p>I need to turn this list of lists into a <code>data.frame</code> of length 5, with each element being a numeric vector with 160 or so elements. </p>
  
  <p>But everything I've tried, from iterating through the list of lists and turning each element with <code>as.numeric(unlist(listHolder[[i]]))</code>, to</p>
  
  <pre><code>data.frame(matrix(unlist(listHolder), nrow = length(totalKeywords), byrow = T))
  </code></pre>
  
  <p>ends up creating a data frame of length 160 or so, with each element being a numeric vector with 5 or so elements. </p>
  
  <p>How do I do what I want?</p>
  
  <p>Attempting <code>data.frame(matrix(unlist(totalKeywords), nrow=132, byrow=T))</code> yields the opposite of what I want - 160 small items each 5 elements long.</p>