title: Direct access to Vector elements in a data.frame in R?
body: <p>Is it possible to directly access elements of vectors in a data.frame?</p>
  
  <pre><code># DataFrame
  nerv &lt;- data.frame(
      c(letters[1:10]),
      c(1:10)
  )
  
  str(nerv)
  
  # Accessing 5th element of the second variable/column
  # This should give "5", but it does NOT work
  nerv[2][5]
  
  # Works, but I need to know the NAME of the column
  nerv$c.1.10.[5]
  </code></pre>
  
  <p>I tried several things, but none of them worked. I just have the index of the column but not the name, since I want to interate several columns using a loop.</p>
  
  <p>It seems that I have a basic knowledge gap and I hope you can help me to fill it.</p>