[R] equivalent of group command of the egen function in Stata

[arun]

Hi,

May be this also helps:

 dat2<-within(dat1,{group<-as.numeric(factor(paste0(dim1,dim2,dim3)))})
 head(dat2)
#        var dim1 dim2 dim3 group
#1 0.5366483    x    1    1     1
#2 0.3081562    y    2    2    17
#3 0.1493687    z    1    3    23
#4 0.3202687    x    2    4     9
#5 0.1177976    y    1    5    15
#6 0.7709756    z    2    1    26
A.K.




----- Original Message -----
From: Francesco Sarracino <f.sarracino at gmail.com>
To: r-help at r-project.org
Cc: 
Sent: Monday, December 10, 2012 9:33 AM
Subject: [R] equivalent of group command of the egen function in Stata

Dear R listers,

I am trying to create a new variable that uniquely identifies groups of
observations in a dataset. So far I couldn't figure out how to do this in
R. In Stata I would simply type:
egen newvar = group(dim1, dim2, dim3)


Please, find below a quick example to show what I am dealing with:
I have a dataset with 4 variables:
var <- runif(50)   ## a variable that I want to group
dim1 <- factor(rep(1:3, length.out= 50), labels = c("x","y","z") ) ## 3
variables that should form the groups
dim2 <- rep(1:2, length.out= 50)
dim3 <- rep(1:5, length.out= 50)

data <- data.frame(var, dim1, dim2, dim3)

I am trying to build a fifth one (let's say: group_id) to uniquely identify
groups of observations as defined by dim1, dim2 and dim3, i.e. 30  groups.

can you please help me figuring out how to do it?
thanks in advance,
f.

-- 
Francesco Sarracino, Ph.D.
https://sites.google.com/site/fsarracino/

    [[alternative HTML version deleted]]

______________________________________________
R-help at 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.