Hi, Arun: Thanks. That's exactly what I need. Spencer
fortune(298)
Don't do as I say, do as Hadley does.
-- Barry Rowlingson (in a discussion about the workflow for writing R
packages, see also fortune(128))
R-devel (September 2011)
On 5/12/2013 2:25 PM, arun wrote:
HI,
Try:
library(plyr)
res1<-ddply(df2aggregate,.(id),summarize,x=sum(x),y=mean(y),a=head(a,1))
res1
# id x y a
#1 a 3 NA <NA>
#2 b 7 2.5 A
#3 c 11 4.5 C
#4 d NA NA E
res1$x<- as.numeric(res1$x)
identical(ag1.2,res1)
#[1] TRUE
A.K.
----- Original Message -----
From: Spencer Graves <spencer.gra...@structuremonitoring.com>
To: R list <R-help@r-project.org>
Cc:
Sent: Sunday, May 12, 2013 4:54 PM
Subject: [R] aggregate.data.frame with NAs and different types
Hello:
Do you have suggestions for how to aggregate a data.frame using
different functions on different columns?
Consider the following example:
df2aggregate <- data.frame(id=rep(letters[1:4], each=2),
x =c(1:6, NA, NA),
y =c(NA, 1:6, NA),
a =c(NA, NA, LETTERS[1:6]),
stringsAsFactors=FALSE)
# Desired output:
ag1.2 <- data.frame(id=letters[1:4],
x =c(3, 7, 11, NA),
y =c(NA, 2.5, 4.5, NA),
a =c(NA, 'A', 'C', 'E'),
stringsAsFactors=FALSE)
I'm thinking of writing a function Aggregate(x, by, FUN, ...),
where x = data.frame, by = vector of names of columns of x, and FUN =
function that would accept as input a data.frame subset of x and would
return a data.frame FUNout, which would be combined using cbind(x[, by],
FUNout), then rbind over all such subset data.frames. However, before I
write this, I'd like to make sure it doesn't already exist. My current
plan is to add it to the Ecdat package.
Suggestions? Should I study "plyr"? fortune(298) ;-)
Thanks,
Spencer
p.s. library(sos); findFn('aggregate.data.frame') returned 4 matches,
none of which seemed to solve this problem. findFn('aggregate
data.frame') returned 133 matches in 71 package. findFn('aggregate')
returned 734 matches in 282 packages. I failed to find anything useful
in the latter two and with other attempts using RSiteSearch, except for
a reference to plyr.
______________________________________________
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.
