title: Why does ls() in R not show global variables?
body: <p>In the code below, LETTERS and letters are global, or in the global search path and reachable through another package (same thing!)</p>
  
  <pre>> LETTERS
   [1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M" "N" "O" "P" "Q" "R" "S"
  [20] "T" "U" "V" "W" "X" "Y" "Z"
  > letters
   [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s"
  [20] "t" "u" "v" "w" "x" "y" "z"
  > ls()
  character(0)
  > a &lt;- "1 2 3"
  > ls()
  [1] "a"
  > rm(a)
  > ls()
  character(0)
  > 
  
  </pre>