Dear Thierry: Thanks for the factor/level advice. I was actually reading about it last night and playing further with my data I was able to make it work with the code below:
options(scipen=3) bargraph <- qplot(factor(Week,levels=c(27:52,1:26)),FryPassage, data=WFBar,geom="bar",fill=I("grey65"),colour=I("goldenrod"), ylab="Numb of Fish",xlab="Week") + scale_x_discrete(breaks=seq(1,52,2)) bargraph That's exactly the same thing you are saying about levels and factors. This is a great learning experience. Thanks again. Felipe D. Carrillo Supervisory Fishery Biologist Department of the Interior US Fish & Wildlife Service California, USA --- On Sat, 1/24/09, ONKELINX, Thierry <thierry.onkel...@inbo.be> wrote: > From: ONKELINX, Thierry <thierry.onkel...@inbo.be> > Subject: RE: [R] ggplot seq > To: mazatlanmex...@yahoo.com, r-h...@stat.math.ethz.ch > Date: Saturday, January 24, 2009, 8:40 AM > Dear Felipe, > > You will need to do some reading on factors. Although the > labels of a > factor can be 'numeric' try are actually just > string representing > numbers. Internally factors are coded as numbers: 1 for the > first level, > 2 for the second and so on. That's why you run into > trouble with > as.numeric() of a factor. > > > A <- factor(c(2, 3, 1, 4), levels = c(3, 4, 2, 1)) > > A > [1] 2 3 1 4 > Levels: 3 4 2 1 > > as.numeric(A) > [1] 3 1 4 2 > > levels(A) > [1] "3" "4" "2" "1" > > as.numeric(levels(A))[A] > [1] 2 3 1 4 > > Defining the factor levels and defining what labels to > display on the > axis are two separate things. Removing the unwanting labels > from the > levels will create missing values. > > > A <- factor(c(2, 3, 1, 4), levels = c(3, 1)) > > A > [1] <NA> 3 1 <NA> > Levels: 3 1 > > With factor you should use scale_x_discrete and not > scale_x_continuous. > Note that I already gave you an example on how to reduce > the number of > labels with scale_x_discrete. Read the argument breaks = > seq(from = 1, > to = 52, by = 4) as put a sequence of tickmark (breaks) > starting from > the first level to the 52th level and skip 4 levels between > two ticks. > > HTH, > > Thierry ______________________________________________ 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.