Martin Maechler
2000-Nov-15 07:30 UTC
[Rd] Re: removing elements that aren't there -- options(check.bounds)
>>>>> "TL" == Thomas Lumley <thomas@biostat.washington.edu> writes:(to R-core, but MM thinks R-devel'ers might want to contribute ..) TL> Now we have option$check.bounds {in R 1.2 (unstable) aka "R-devel"} TL> could we consider allowing negative TL> subscripts outside the array bounds: TL> x <- 1:3 TL> x[-4] TL> is an error in R but not in S. TL> I think there is a much stronger case for x[-4] to succeed than for TL> x[4], which we do allow. I tend to agree. Note that currently, options(check.bounds = TRUE) only affects `sub-assignment', i.e. the "[<-" functions, and not `sub-setting' (aka "[") : > options(check.bounds = TRUE) > x[4] [1] NA > x[-4] Error: subscript out of bounds > x[4] <- 4 Warning message: assignment outside vector/list limits (extending from 3 to 4) > x[-5] Error: subscript out of bounds > x[5] [1] NA I tend to think that options(check.bounds = TRUE) should - also warn when `subsetting' outside given bounds - only warn in the above x[-4] case -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel 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-devel-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._