Odd behaviour of subset indexing (x:y).
on 01/20/2009 05:01 PM John Sorkin wrote:
R 2.8.1 windows XP I don't understand the output from x[iS+1:iE] produced by the code below: x = c(1,2,3,4,5) x [1] 1 2 3 4 5 iS=2 # start position iE=4 # end position [iS:iE] [1] 2 3 4 # I don't understand the results of the command below. I would expect to see 3, 4, not 3, 4, 5, NA x[iS+1:iE] [1] 3 4 5 NA Thanks, John
Operator precedence. Note: # You are asking for indices 3:6 and of course x[6] does not exist # hence the NA # Equivalent to: iS + (1:iE)
iS + 1:iE
[1] 3 4 5 6 # This is what you want
(iS + 1):iE
[1] 3 4 HTH, Marc Schwartz