I've got a data frame with panel-data, subjects' characteristic through the time. I need create a column with a sequence from 1 to the maximum number of year per every subject. For example, if subject 1 is in the data frame from 2000 to 2005, I need the following sequence: 1,2,3,4,5,6.
Below is a small fraction of my data. The last column (exp) is what I trying to get. Additionally, if you have a look at the first subject (13) you'll see that in 2008 the value of qtty is zero. In this case I need just a NA or a code (0,1, -9999), it doesn't matter which one.
Below the data is what I did to get that vector, but it didn't work.
Any help will be much appreciated.
subject season qtty exp
13 2000 29 1
13 2001 29 2
13 2002 29 3
13 2003 29 4
13 2004 29 5
13 2005 27 6
13 2006 27 7
13 2007 27 8
13 2008 0 NA
28 2000 18 1
28 2001 18 2
28 2002 18 3
28 2003 18 4
28 2004 18 5
28 2005 18 6
28 2006 18 7
28 2007 18 8
28 2008 18 9
28 2009 20 10
28 2010 20 11
28 2011 20 12
28 2012 20 13
35 2000 21 1
35 2001 21 2
35 2002 21 3
35 2003 21 4
35 2004 21 5
35 2005 21 6
35 2006 21 7
35 2007 21 8
35 2008 21 9
35 2009 14 10
35 2010 11 11
35 2011 11 12
35 2012 10 13
My code:
numbY<-aggregate(season ~ subject, data = toCountY,length)
colnames(numbY)<-c("subject","inFish")
toCountY$inFish<-numbY$inFish[match(toCountY$subject,numbY$subject)]
numbYbyFisher<-unique(numbY)
seqY<-aggregate(numbYbyFisher$inFish, by=list(numbYbyFisher$subject), function(x)seq(1,x,1))
I am using ddply and I distinguish 2 cases:
Either you generate a sequence along subjet and you replace by NA where you have qtty is zero
ddply(dat,.(subjet),transform,new.exp=ifelse(qtty==0,NA,seq_along(subjet)))
Or you generate a sequence along qtty different of zero with a jump where you have qtty is zero
ddply(dat,.(subjet),transform,new.exp={
hh <- seq_along(which(qtty !=0))
if(length(which(qtty ==0))>0)
hh <- append(hh,NA,which(qtty==0)-1)
hh
})