[R] Identifying last record in individual growth data over different time intervalls

[Rainer M. Krug]

Hi

jim holtman wrote:
> What is wrong with the method that you have?  It looks reasonable

Actually there is nothing wrong with the approach I am using - it just
seemed to be quite complicated and I assumed that there is an easier
approach around.

The dataset is not that large that I really have to worry about efficiency.

Thanks a lot ,

Rainer


> efficient.  As with other languages, there are always other ways of doing
> it.  Here is another to consider, but it is basically the same:
> 
>> sapply(split(t, t$plate), function(x) x$id[which.max(x$year)])
>      15      20      33      43      44      47      64     D72    S200
> S201    S202    S203    S204
> 2006001 2006003 2006005 2006007 2006008 2006009 2006014 2006015 2006016
> 2006017 2004095 2006019 2006020
>    S205    S206    S207    S208    S209    S210    S211    S212    S213
> S214    S215    S216    S217
> 2006021 2006022 2006023 2006024 2006025 2006026 2006027 2006028 2006029
> 2006030 2006031 2006032 2006033
>    S218    S219    S220    S222    S223    S224
> 2006034 2006035 2006036 2006037 2006038 2006039
> 
> 
> 
> On 3/5/07, Rainer M. Krug <Rainer.Krug at uct.ac.za> wrote:
>> Hi
>>
>> I have a plist t which contains size measurements of individual plants,
>> identified by the field "plate". It contains, among other, a field
>> "year" indicating the year in which the individual was measured and the
>> "height". The number of measurements range from 1 to 4 measurements in
>> different years.
>> My problem is that I would need the LAST measurement. I only came up
>> with the solution below which is probably way to complicated, but I
>> can't think of another solution.
>>
>> Does anybody has an idea how to do this more effectively?
>>
>> Finally I would like to have a data.frame t2 which only contains the
>> entries of the last measurements.
>>
>> Thanks in advance,
>>
>> Rainer



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Leslie Hill Institute for Plant Conservation
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