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

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