kriging output

Dave Depew wrote:
 Thanks,
 This worked.

 I'm still confused why the if else statement didn't work...
 If one wanted to do conditional arithmetic would a for statement bee
 needed?

 e.g.
 meuse.grid[["class"]] = for(i in 1:length(meuse.grid[["dist"]])){
 if (meuse.grid[["dist"]]<0.5)
 {meuse.grid[["class"]]=10*meuse.grid[["dist]]} else
 {meuse.grid[["class"]]=100* meuse.grid[["dist"]]}
 }

I'd say
meuse.grid$class = ifelse(meuse.grid$dist < .5, 10, 100) * meuse.grid$dist
Right. ifelse() is vectorised, but if() else is not, so the vector 
condition in ifelse() splits out nicely, but if() else is flow control on 
a scalar condition. The above for loop looks redundant anyway (no use of 
index), but the if() else construction wouldn't work either - as you 
found out earlier.

For things like this, Braun & Murdoch is good (and from Canada!); if you 
read German, Uwe Ligges' book is recommended. It's also in the online 
Introduction to R, section 9.2.1, which explains the previous paragraph 
much more clearly than I can.

Roger
assigning the result from a for statement also does not yield a beauty price 
if you ask me, but that might be my  backgrounds in C, long ago.
--
Edzer

_______________________________________________
R-sig-Geo mailing list
R-sig-Geo at stat.math.ethz.ch
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no

kriging output

Thread (5 messages)