** variable indexing
   :PROPERTIES:
   :DATE:     2010-04-23
   :END:
#+TBLNAME: MyTable
 |   X |  Y |
 |-----+----|
 |   0 |  0 |
 |   1 |  1 |
 |   2 |  4 |
 |   3 |  9 |
 |   4 | 16 |
 |   5 | 25 |
 |-----+----|
 | Sum | 55 |
 #+TBLFM: $2=$1*$1::@8$2=vsum(@2..@-1)

#+begin_src python :var sum=MyTable[2:7,1] :exports none
   return sum
#+end_src

#+name:
| 0 | 1 | 4 | 9 | 16 | 25 |

#+begin_src python :var sum=MyTable[9,1] :exports none
   return sum
#+end_src

#+name:
: 55

#+begin_src gnuplot :var data=MyTable[1:-2] :var sum=MyTable[7,1]
:results silent :exports none
  reset
  set label "Sum: %.0f",sum at graph 0.03, graph 0.93
  plot data with linespoints
#+end_src