tapply output as a dataframe

do.call(rbind,a)

i use tapply and by often, but i always end up banging my head against
the wall with the output.

is there a simpler way to convert the output of the following tapply to
a dataframe or matrix than what i have here:

# setup data for tapply
dt = data.frame(bucket=rep(1:4,25),val=rnorm(100))
fn = function(x) {
?ret =
c(unname(quantile(x,probs=seq(.25,.75,.25),na.rm=T)),mean(x,na.rm=T))
}
a = tapply(dt$val,dt$bucket,fn)

# i seem to be doing way more work than i should here....
n = names(a)
mat = NULL
for (i in 1:length(n)) {
?mat = rbind(mat,unname(unlist(a[i])))
}
row.names(mat) = n

thank you!

-----Original Message-----
From: Jorge Ivan Velez [mailto:jorgeivanvelez at gmail.com] 
Sent: Monday, April 13, 2009 12:50 PM
To: Dan Dube
Cc: r-help at r-project.org
Subject: Re: [R] tapply output as a dataframe


Dear Dan,

Try this:

do.call(rbind,a)


HTH,

Jorge



On Mon, Apr 13, 2009 at 12:41 PM, Dan Dube <ddube at advisen.com> wrote:


	i use tapply and by often, but i always end up banging 
my head against
	the wall with the output.
	
	is there a simpler way to convert the output of the 
following tapply to
	a dataframe or matrix than what i have here:
	
	# setup data for tapply
	dt = data.frame(bucket=rep(1:4,25),val=rnorm(100))
	fn = function(x) {
	 ret =
	
c(unname(quantile(x,probs=seq(.25,.75,.25),na.rm=T)),mean(x,na.rm=T))
	}
	a = tapply(dt$val,dt$bucket,fn)
	
	# i seem to be doing way more work than i should here....
	n = names(a)
	mat = NULL
	for (i in 1:length(n)) {
	 mat = rbind(mat,unname(unlist(a[i])))
	}
	row.names(mat) = n
	
	thank you!