--- On Thu, 9/11/08, Adaikalavan Ramasamy <[EMAIL PROTECTED]> wrote:
From: Adaikalavan Ramasamy <[EMAIL PROTECTED]>
Subject: Re: [R] Calculate mean/var by ID
To: "Jorge Ivan Velez" <[EMAIL PROTECTED]>
Cc: "liujb" <[EMAIL PROTECTED]>, r-help@r-project.org
Da
From: Adaikalavan Ramasamy <[EMAIL PROTECTED]>
Subject: Re: [R] Calculate mean/var by ID
To: "Jorge Ivan Velez" <[EMAIL PROTECTED]>
Cc: "liujb" <[EMAIL PROTECTED]>, r-help@r-project.org
Date: Thursday, September 11, 2008, 10:28 PM
A slight variation of what Jorge
A slight variation of what Jorge has proposed is:
f <- function(x) c( mu=mean(x), var=var(x) )
do.call( "rbind", tapply( df$value, df$ID, f ) )
mu var
111 4.33 4.33
138 6.00 4.67
178 5.00 8.00
Regards, Adai
Jorge Ivan Velez wrote:
Dear J
Dear Julia,
Try also
x=read.table(textConnection("IDvalue
111 5
111 6
111 2
178 7
178 3
138 3
138 8
138 7
138 6"),header=TRUE)
closeAllConnections()
attach(x)
do.call(rbind,tapply(value,ID, function(x){
res=c(mean(x,na.rm=TRUE),var(x,na.rm=TRUE))
names(res
aggregate(value,list(ID=ID),mean)
aggregate(value,list(ID=ID),var)
--Adam
On Thu, 11 Sep 2008, liujb wrote:
Hello,
I have a data set that looks like this.
IDvalue
111 5
111 6
111 2
178 7
178 3
138 3
138 8
138 7
138 6
.
.
.
I'd like to calculate the me
Try:
with(x, sapply(list(mean, var), function(x)tapply(value, ID, x)))
On Thu, Sep 11, 2008 at 2:45 PM, liujb <[EMAIL PROTECTED]> wrote:
>
> Hello,
>
> I have a data set that looks like this.
> IDvalue
> 111 5
> 111 6
> 111 2
> 178 7
> 178 3
> 138 3
> 138 8
> 138
Hello,
I have a data set that looks like this.
IDvalue
111 5
111 6
111 2
178 7
178 3
138 3
138 8
138 7
138 6
.
.
.
I'd like to calculate the mean and var for each object identified by the ID.
I can in theory just loop through the whole thing..., but is th
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