Here is a different approach to achieving what I think you want using
summarize() in the Hmisc package:
library(Hmisc)
mydata <- data.frame(a = sample(1:5,200,replace=TRUE),
b = sample(c("v1","v2","v3"),200,replace=TRUE),
c = sample(c(11,22,33),200,replace=TRUE),
y = runif(200))
attach(mydata)
summarize(y, llist(a, b, c),
function(x){c(min=min(x),
max=max(x),
median=round(median(x),digits=2),
mean=round(mean(x),digits=2))},
stat.name="min")
detach(mydata)
bogdan romocea wrote:
Dear useRs,
Given this code I end up with a list of class "by":
a <- sample(1:5,200,replace=TRUE)
b <- sample(c("v1","v2","v3"),200,replace=TRUE)
c <- sample(c(11,22,33),200,replace=TRUE)
data <- runif(200)
grouped <- by(data,list(a,b,c),function(x) {c(min=min(x),max=max(x),
median=round(median(x),digits=2),mean=round(mean(x),digits=2))})
dfr <- do.call("rbind",grouped) #the levels are missing
#----------
grouped
typeof(grouped)
class(grouped)
dimnames(grouped)
How do I get at the levels of the 'group by' variables for each
subset? For example, from this part of the "by" list I want 4, v2 and
33:
: 4
: v2
: 33
min max median mean
0.3897450 0.9215315 0.7300000 0.6700000
---------------------------------------
Thank you,
b.
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