You also might want to look at demo("gsubfn-cut")
On Tue, Dec 1, 2009 at 2:41 PM, David Winsemius <dwinsem...@comcast.net>wrote: > Starting with the head of a 499 element matrix whose column names are now > the labels trom a cut() operation, I needed to get to a vector of midpoints > to serve as the basis for plotting a calibration curve ( exp(linear > predictor) vs. : > > > dput(head(dimnames(mtcal)[2][[1]])) # was starting point > > > testvec <- c("(-8.616,-3.084]", "(-3.084,-2.876]", "(-2.876,-2.756]", > "(-2.756,-2.668]", > "(-2.668,-2.597]", "(-2.597,-2.539]") > > I started this message with the thought of requesting an answer but kept > asking myself if I really had check the docs and tested my understanding. I > eventually solved it using the gsubfn from the gsubfn package: > > testintvl <-as.numeric(gsubfn("\\((-?[[:digit:]]+.?[[:digit:]]*), > (-?[[:digit:]]+.?[[:digit:]]*)\\]", > ~ (as.numeric(x)+as.numeric(y))/2, testvec)) > > # I did discover that carriage returns in the middle of the pattern will > not give desired results, so if this is broken by your mail-client, be sure > to rejoin in the console. > > The extra "?"'s after the decimal point are in there because I had 4 NA's > around the median linear predictor: > > > dimnames(mtcal)[2][[1]][which(is.na(testintvl))] > [1] "(-1.008,-1]" "(-1,-0.9922]" "(0.9914,1]" "(1,1.009]" > > So a better test vector would be: > > testvec <- c("(-8.616,-3.084]", "(-3.084,-2.876]", "(-2.876,-2.756]", > "(-2.756,-2.668]", > "(-2.668,-2.597]", "(-2.597,-2.539]", "(-1.008,-1]", "(-1,-0.9922]", > "(0.9914,1]", "(1,1.009]" ) > > > testintvl > <-as.numeric(gsubfn("\\((-?[[:digit:]]+.?[[:digit:]]*),(-?[[:digit:]]+.?[[:digit:]]*)\\]", > + ~ (as.numeric(x)+as.numeric(y))/2, testvec)) > > > testintvl > [1] -5.8500 -2.9800 -2.8160 -2.7120 -2.6325 -2.5680 -1.0040 -0.9961 > 0.9957 1.0045 > > I offer this to those who may feel regex challenged (as I often do). The > gsubfn function is pretty slick. I don't see an author listed for the > function, but the author of the package documents is Gabor Grothendieck. > > -- > > David Winsemius, MD > Heritage Laboratories > West Hartford, CT > > ______________________________________________ > 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.