title: Extract variable names from list or vector in R
body: <p>Assuming:</p>
  
  <pre><code>aa = c('A','B','C')
  bb = c('D','E','F')
  list1 = list(aa,bb)
  vect1 = c(aa,bb)
  </code></pre>
  
  <p>Is there a way to extract the variable names as strings ('aa', 'bb') from either list1 or vect1? 
  Is this information being stored in lists and vectors? If not, what would be the appropriate format?</p>
  
  <p>Thanks in advance!</p>