[R] boxplot() from list

[John Fox]

Dear Laura,

You don't say what kind of "objects" are in the list, but suppose that they
are matrices; here's a scaled-down example using 3 list elements:

M1 <- matrix(rnorm(30*4), 48, 4)
M2 <- matrix(rnorm(30*4), 48, 4)
M3 <- matrix(rnorm(30*4), 48, 4)
L <- list(M1=M1, M2=M2, M3=M3)

par(mfrow=c(3, 4))
lapply(L, function(x) apply(x, 2, boxplot))

I hope that this helps,
 John 

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Laura Quinn
> Sent: Sunday, September 12, 2004 10:10 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] boxplot() from list
> 
> I have a list containing 48 objects (each with 30 rows and 4 
> columns, all numeric), and wish to produce 4 boxplot series 
> (with 48 plots in each) , one for each column of each object.
> 
> Basically I want a boxplot from boxplot(mylist[[]][,i])
> 
> for i in 1:4. It seems that I can create a boxplot of length 
> 48 from the entire list, but I don't seem able to subscript 
> to return 4 boxplots from the list - I have also tried to 
> create 4 new lists (one for each column of each object) by 
> using variations on the following, but none seems to work:
> 
> newlist<-oldlist[,1]
> newlist<-oldlist[[]][,1]
> newlist<-oldlist[[]][,$colone]
> 
> can anyone please offer some insight??
> 
> Thanks in advance,
> 
> Laura Quinn
> Institute of Atmospheric Science
> School of Earth and Environment
> University of Leeds
> Leeds
> LS2 9JT