Hi:
Here's another way to do it with the plyr package, also not terribly
elegant. It assumes that rel.head is a factor in your original data
frame:
> str(df)
'data.frame': 11 obs. of 2 variables:
$ ID : Factor w/ 6 levels "17100","17101",..: 1 1 2 3 4 4 5 5 5 6 ...
$ rel.head: Factor w/ 3 levels "1","2","3": 1 3 1 1 1 2 1 2 3 1 ...
If this is not the case in your data, then you need to modify the
function f below accordingly. (This is why use of dput() is preferred
when sending example data to R-help, BTW.)
library('plyr')
f <- function(d) {
tvec <- factor(c(1, 3), levels = 1:3) # target vector
if(nrow(d) != 2L) {d$dummy <- rep(0, nrow(d)); return(d)}
# If the first if statement is FALSE, then the following code is run:
d$dummy <- ifelse(!identical(d[, 2], tvec), 0, 1)
d
}
ddply(df, .(ID), f)
ID rel.head dummy
1 17100 1 1
2 17100 3 1
3 17101 1 0
4 17102 1 0
5 17103 1 0
6 17103 2 0
7 17104 1 0
8 17104 2 0
9 17104 3 0
10 17105 1 1
11 17105 3 1
HTH,
Dennis
On Tue, Oct 4, 2011 at 8:44 AM, <gra...@stat.columbia.edu> wrote:
> Hi all,
>
> I have a dataset of individuals where the variable ID corresponds to the
> identification of the household where the individual lives. rel.head stands
> for the relationship with the household head. so rel.head=1 is the household
> head, rel.head=2 is the spouse, rel.head=3 is the children.
>
> Here is an example to see how it looks like:
>
> df<-data.frame(ID=c("17100", "17100", "17101", "17102", "17103", "17103",
> "17104", "17104", "17104", "17105", "17105"),
> rel.head=c("1","3","1","1","1", "2", "1", "2", "3", "1", "3"))
>
>
> I want to add a dummy variable that is equal to 1 when these conditions
> held simultaneously :
>
> a) the number of rows with same ID is equal to 2
> b) the variable rel.head=1 and rel.head=3
>
>
> So my ideal output is:
>
> ID rel.head added.dummy
> 1 17100 1 1
> 2 17100 3 1
> 3 17101 1 0
> 4 17102 1 0
> 5 17103 1 0
> 6 17103 2 0
> 7 17104 1 0
> 8 17104 2 0
> 9 17104 3 0
> 10 17105 1 1
> 11 17105 3 1
>
> Is there a simple way to do that?
> Can somebody help?
>
> Thanks in advance,
> Grazia
>
> ______________________________________________
> 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.
>
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