You can also use if (cond) then {something} if you don't like ifelse()
function. See ?Control.David 2009/6/23 Peter Flom <peterflomconsult...@mindspring.com> > >Dieter Menne wrote: > >> > >>>> IF TYPE='TRUCK' and count=12 THEN VEHICLES=TRUCK+((CAR+BIKE)/2.2); > >>> vehicles <- ifelse(TYPE=='TRUCK' & count=12, TRUCK+((CAR+BIKE)/2.2), > NA) > >>> > >>> > >> > >> Read both versions to an audience, and you will have to admit that this > is > >> one of the cases where SAS is superior. > > And Peter Dalgaard replied > > >That's not entirely clear. For instance, SAS is not being clear about > >what happens when the condition is FALSE. > > > > Well, OK, but then it is easy to add an ELSE, and I do find a structure > such as > > IF X = 1 THEN .... > ELSE IF X = 2 THEN ... > ELSE X = > > quite a lot easier to both read and write than the equivalent in R. I also > find the DO loops > in SAS clear. > > > >SAS is also not distinguishing comparison and assignment, but then again > >you don't accidentally do count=12 when you mean count==12.... > > > >As a generic matter, SAS (the DATA step) is generally good at things > >that are done by sequential sweeps through a data file. The shortcomings > >come in when you do things that can't be done sequentially, or require > >substantial rearranging of data first. x - ave(x,g,median) is an example > >which IIRC requires > > > >proc sort > >proc means by group (saving medians to data set) > >data step (merge and subtract) > > > > True. But two points: > 1) Speaking only for me, but I use an IF THEN ELSE type structure a lot > more often then I have to do something like the second example. > > 2) Again, speaking for me, the second sort of thing seems like it OUGHT to > be hard, while IF THEN seems like it ought to be easy. This may be because > I learned SAS before R > > > Peter > > Peter L. Flom, PhD > Statistical Consultant > www DOT peterflomconsulting DOT com > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
