Two short replies to Thomas's answer: "strata" is from the survival package. "interaction" and "strata" do slightly different things. The order in which the levels are cycled is different and In both cases the new level set is the cartesian product of all the component level sets, but with strata any vacant levels are pruned, with interaction they are not. Bill Venables. -----Original Message----- From: Thomas Lumley [mailto:tlumley at u.washington.edu] Sent: Tuesday, October 01, 2002 11:55 PM To: juli g. pausas Cc: r-help Subject: Re: [R] 2 plots sharing axis / combining factors
On Mon, 30 Sep 2002, juli g. pausas wrote:
- How could I convert 2 factor variables in a single factor variable
which is the combination of the other 2.
Example:
lith: a factor 2 levels "ca", "ma"
sp: a factor with 2 levels, "ph", "qi"
and I'd like to obtain:
splith: a factor with 4 levels: phma, phca, qima, qica
strata(lith,sp) or interaction(lith,sp) -thomas -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-. -.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._. _._ -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._