Dear R friends,
I have a matrix with 2060 rows and 41 columns. One column is Date, another is
Transect, and another is Segment. I want to ensure that there are 9 Transects
(1 to 9) for each Date, and 8 Segments (1 to 8) for each Transect in the
matrix, by inserting rows where these are missing.
I am new to coding, but am trying to write a loop which checks if each of the
transects already exists, and then adds a row in the appropriate place if it
doesn't (I have not tackled the segment part, since I am having problems with
the Transect part). I have simplified the matrix to show the code I so far
have. The code seems to do the right thing for the first date, but not on
subsequent dates. The code is:
AerialSurveysm<-matrix(c("13/06/2006","19/06/2006","19/06/2006","19/06/2006","19/06/2006","19/06/2006","26/06/2006",4,7,7,7,8,8,3,
2,5,5,4,4,5,2), nrow = 7, ncol = 3)
colnames(AerialSurveysm) <- c("Date","Transect","Segment")
i=1 #start iteration for all dates
k=2 #start iteration for all transects
m<-unique(AerialSurveysm[,1])
for (i in 1:length(m)) { #for each date
for (k in 1:9) { #do the following for the total number of
transects that there are (1 to 9)
NewDat <-subset(AerialSurveysm, AerialSurveysm[,1]== m[i]) #select date
to work on beginning with 1st
indx<-which(AerialSurveysm[,1]==m[i])
indx<-indx[[1]]
Check<-which(NewDat[,2]==k)
NewRow<-c(c(m[i]),k,0)
if(is.empty(Check)==TRUE)#if the selected date does not have a transect
equal to transect k
AerialSurveysm<-insertRow(AerialSurveysm,indx,NewRow) #add a row to
AerialSurveys.m in the location of the correct date
}
i=i+1
}
Thanks for any hints or thoughts on this (maybe I'm tackling it completely the
wrong way!)!
Chandra
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