[R] create matrix

[John Kane]

It depends on how you have your data laid out.  This
is clumsy but I think it will work.  There should be
an easier way than a loop but I don't see it.  People
with more experience in R will likely have much better
solutions.

In any case it sure beats Excel or any other
spreadsheet :)
======================================================

# Create mock data set (data.frame) with four cows.  
i <- 1:4
cows <- paste("cow",i, sep="")
food <- sample(c("hay", "grain"), 4, replace=TRUE)
cattle <- data.frame(cows, food)

# Vecctor of longevity data
age <- sample(3:9, 4, replace = TRUE)

#Create empty list
mylist <- NULL

for(i in 1:length(cattle[,1])) {
count <-(seq(1,age[i]))
dead <- c(rep(0,length(count)-1),1)
newcow <- data.frame(merge(data.frame(cattle[i,]),
count),dead)
mylist[[i]] <- newcow
}

# Turn mylist into a data.frame
mydata  <- do.call(rbind, mylist)

# Get rid of unneeded count varable.
mydata <- mydata[,-3]
mydata

======================================================
--- Felix Zajitschek - UNSW
<felix.zajitschek at unsw.edu.au> wrote:

> Hi all,
>  
> I have a dataset consisting of 5 columns and over
> 5000 rows. Each row
> gives information about an individual animal,
> including longevity, i.e.
> at what age an animal died.
> For the model I use I need to create n rows for each
> animal, n being its
> longevity, and a new column 'survival' with a binary
> 0/1 outcome. When
> an animal died e.g. at age 5, there have to be 5
> rows of identical data,
> except 4 with 0 (=alive) for 'survival', and 1 row
> with '1' for
> 'survival'.
>  
> I thought of creating matrices for each individual,
> adding first one
> column 'survival' containing zeros to the original
> dataset, then
> creating matrices with data = 'the vector containing
> all elements of an
> individual/row' ([1,], nrow = [a,b], exctracting the
> element for
> longevity, and then with byrow = TRUE letting the
> data be filled in by
> row. At the end I would have to set the last element
> in 'survival' to
> '1', and then combine all matrices into one single
> one.
>  
> So far I've used Excel to create these datesets
> manually, but with more
> than 1000 individuals this gets really tedious. I
> haven't used R before
> for this sort of a bit more advanced data
> manipulation, and I would
> really appreciate any input/primer about how people
> would go about doing
> this.
>  
> Thanks,
> Felix
>  
>  
>
______________________________________________________________
> ::Felix Zajitschek 
> Evolution & Ecology Research Centre
> School of Biological, Earth and Environmental
> Sciences 
> University of New South Wales - Sydney NSW 2052 -
> Australia 
> Tel           +61 (0)2 9385 8068
> Fax          +61 (0)2 9385 1558 
> eMail       <mailto:felix.zajitschek at unsw.edu.au>
> felix.zajitschek at unsw.edu.au
>  
>
<http://www.bees.unsw.edu.au/school/researchstudents/zajitschekfelix.htm
> l>
>
www.bees.unsw.edu.au/school/researchstudents/zajitschekfelix.html
>  
> 
> 	[[alternative HTML version deleted]]
> 
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