[R] Basic population dynamics

[Moshe Olshansky]

Assuming that at the end all of them are dead, you can do the following: 

sum(deaths)-cumsum(deaths)

Regards,

Moshe.

--- On Wed, 2/9/09, Frostygoat <frostygoat at gmail.com> wrote:

> From: Frostygoat <frostygoat at gmail.com>
> Subject: [R] Basic population dynamics
> To: r-help at r-project.org
> Received: Wednesday, 2 September, 2009, 4:48 AM
> 
> Hello,
> 
> For insect mortality data I'm trying to get an R script
> that will take
> the data from the raw form and convert it to Lx (%
> survival) for a
> number of treatments.  The raw data has the number of
> days lived for
> each individual for the respective treatment.  Thus,
> for example, when
> R selects the data for a single treatment I end up with the
> following
> vectors:
> 
> >day=seq(from=0,to=6)
> >deaths=c(0,0,2,0,0,1,6)
> 
> where deaths is the number of deaths on a given day. Now I
> need to
> create a new vector with the number alive for each day and
> this is
> where I'm stuck... I've tried to work various for and while
> loops but
> haven't had success.  The vector should be:
> 
> >Alive=c(9,9,7,7,7,6,0)
> 
> I realize it is a very basic problem that is easily
> accomplished in
> one's head or on a spreadsheet but in the context of the
> size of the
> data set I wish to have R do it for me. I would welcome
> any
> suggestions please.
> 
> Best regards.
> 
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