try this:
Dat <- read.table(textConnection(
"id year y z
1 a 2000 1 1
2 b 2000 NA 2
3 b 2001 3 3
4 c 1999 1 1
5 c 2000 2 2
6 c 2001 4 NA
7 c 2002 5 4
8 d 1998 6 5
9 d 1999 5 NA
10 d 2000 6 6
11 d 2001 7 7
12 d 2002 3 6"
), header = TRUE)
closeAllConnections()
n.years <- 3 # the threshold
na.ind <- !rowSums(is.na(Dat[-(1:2)])) # the variables of interest
ind <- ave(na.ind, Dat$id, FUN = function (x) any(cumsum(x) > n.years))
Dat[ind, ]
I hope it helps.
Best,
Dimitris
On 7/22/2010 11:18 AM, Christian Schoder wrote:
Dear R-user,
a few weeks ago I consulted the list-serve with a similar question.
However, my task changed a little but sufficiently to get lost again. So
I would appreciate any help on the following issue.
I use the plm package and work with firm-level data in a panel. I would
like to eliminate all firms that do not fulfill the requirement of
having an observation in every variable used for at least x consecutive
years.
For illustration of the problem assume the following data set
data
id year y z
1 a 2000 1 1
2 b 2000 NA 2
3 b 2001 3 3
4 c 1999 1 1
5 c 2000 2 2
6 c 2001 4 NA
7 c 2002 5 4
8 d 1998 6 5
9 d 1999 5 NA
10 d 2000 6 6
11 d 2001 7 7
12 d 2002 3 6
where id is the index of the firm, year the index for the year, and y
and z are variables. Now, I would like to get rid of all firms with,
let's say, less than 3 consecutive years in which there are observations
for every variable. Hence, the procedure should yield
data.reduced
id year y z
1 d 1998 6 5
2 d 1999 5 NA
3 d 2000 6 6
4 d 2001 7 7
5 d 2002 3 6
Thank you very much for any help!
Cheers, Christian
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and provide commented, minimal, self-contained, reproducible code.
--
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center
Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014
______________________________________________
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.
