[R] Zero Index Origin?

[Barry Rowlingson]

Bob Cain wrote:
>  At
> this early stage of my learning I can't yet determine if there is a way 
> to effect what in APL was zero index origin, the ordinality of indexes 
> starts with 0 instead of 1.  Is it possible to effect that in R without 
> a lot of difficulty?
> 

  Clearly R wasn't written by Dijkstra:

http://www.cs.utexas.edu/users/EWD/ewd08xx/EWD831.PDF

  This text was pointed out to me when I started using Python, which has 
zero-based indexing. Python can look so much like R, but there are 
subtle differences.


R:
  > x=c(5,4,3,2,1)
  > x[3]
  [1] 3
  > x[2:4]
  [1] 4 3 2

compare:

Python:
  >>> x=[5,4,3,2,1]
  >>> x[3]
   2
  >>> x
   [5, 4, 3, 2, 1]
  >>> x[2:4]
   [3, 2]

  A single element from a sequence in python is indexed from zero, hence 
x[3] == 2, but a range indexes from the commas between the limits of the 
range. Hence x[2:4] is the elements between comma 2 and comma 4 - hence 
its only 2 elements.

  Did my head in when I first started pythoning. Flipping between R and 
python is not recommended, kudos to all those involved in such R-python 
links...

Baz