[R] averaging rows on a data.frame according to a factor

Dear all, I apologize for the newbie question, but I'm stuck. I have a data frame in the following form: dat<-as.data.frame(cbind(c("a","a","a","b","b"), c(1,2,3,3,2),c(4,3,5,4,4))) I need a way to generate a new dataframe with the average for each factor. The result should look like: res<-as.

[R] histogram with bars colored according to a vector of values

Dear all, Let's say I have the following data.frame: dat<-data.frame(x=rnorm(100), y=rnorm(100,2)) and I plot a histogram of variable x, somethink like: hist(dat$x, breaks=-5:5) Now, I'd like to color each bar according to the mean of the cases according to y. For instance, the color of the bar

[R] help with PCA

Dear all, If I do a PCA like this: dat<-matrix(rnorm(30),ncol=3) res<-prcomp(dat) Now, imagine that I got new data that I want to project onto the original PC axes. How do I do that? Thanks! John __ R-help@r-project.org mailing list https://stat.eth

Re: [R] multiple values in one column

On Apr 6, 2012, at 9:09 AM, John D. Muccigrosso wrote: > I have some data files in which some fields have multiple values. For example > > first last sex major > John Smith M ANTH > Jane DoeF HIST,BIOL > > What's the best R-like way to handle thes

[R] multiple values in one column

I have some data files in which some fields have multiple values. For example first last sex major John Smith M ANTH Jane DoeF HIST,BIOL What's the best R-like way to handle these data (Jane's major in my example), so that I can do things like summarize the other fields by

[R] circles()

I cannot for the life of me figure this out: What's the parameter to fill in with color circles made with circles()? col changes the line color, but all I see in the help is a reference to "additional graphic parameters", and no examples via google. Thanks! John Muccigrosso __

Re: [R] barplot and NA

On 12 Mar 2012, at 12:47 , S Ellison wrote: > Yes, to the extent that the default barplot plots the height of the bar so > far as the sum of teh values so far, starting at teh first. For your first > vector, no problem; for your second, the highest value is undefiuned, for the > third, the sum

[R] barplot and NA

Am I wrong that barplot is supposed to just skip NAs, and continue with the rest of the data in a matrix column? That's how I read various posts on the subject. But that's not what happens for me with R64.app (on a Mac, obviously). For example: d0 <- as.matrix(c(2,3,4)) d1 <- as.matrix(c(2,3,N