R help - May 2005 - aggregate and stack

Dear All,

I have tried to calculate tree mean growth but I think the structure I used
below (growthresumo) is not the most elegant, even though it worked. The only
problem I had in this first part was that  I cannot use 'summary', just
'mean' (sorry but 'R' is pretty new for me).
>growthresumo <-
aggregate(growth[,c(16,19,23,27,31,35,39,43,47,52,56,60,64,68,72,76,81,85,89,93,97,101,105,109,113,117,121,125,129,133,137,
141,145,149,153,157,161,165,169,173,177,181,185,189,194,197,201,205,209,213,217,221,225,229,233,237,241)],
by=(growth[,c(3,8)]),MEAN,na.rm=TRUE)

#after growth is calculated, I want to stack the results in just one colunm.  
>growthvertical <- c(growthresumo[,3],...,growthresumo[,50]) # this is
very time consuming though
>Parcel <-
c("C9","S8"..."C9","S8") # 50 items
>date < c("DATE1"...."DATE50")
>growthpermonth <- data.frame(Parcel, Date, growthvertical)
Thank you very much!

Paulo

Paulo Brando
Inst. de Pesquisa Ambiental da Amazônia (IPAM)
Rua Rui Barbosa,136.
68.005.080 Santarém, PA, Brasil.
Fone/Fax ++ 55 93 522 5538
www.ipam.org.br
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Dear Paulo,

On May 25, 2005, at 8:01 PM, Paulo Brando wrote:
> Dear All,
>
> I have tried to calculate tree mean growth but I think the structure I  
> used below (growthresumo) is not the most elegant, even though it  
> worked. The only problem I had in this first part was that  I cannot  
> use 'summary', just 'mean' (sorry but 'R' is pretty
new for me).
>
In case you didn't notice, help(aggregate) indicates that 'FUN'
should be a scalar function, so summary won't work for that reason.
>> growthresumo <-  
>> aggregate(growth[,c(16,19,23,27,31,35,39,43,47,52,56,60,64,68,72,76,81 
>> ,85,89,93,97,101,105,109,113,117,121,125,129,133,137,
> 141,145,149,153,157,161,165,169,173,177,181,185,189,194,197,201,205,209 
> ,213,217,221,225,229,233,237,241)],
> by=(growth[,c(3,8)]),MEAN,na.rm=TRUE)
>
It's hard to know where 'growth' came from. Is it your own
data.frame,
or from a package? It's better to provide a reproducible or toy example
(as you'll often read here).
> #after growth is calculated, I want to stack the results in just one  
> colunm.
>
>> growthvertical <- c(growthresumo[,3],...,growthresumo[,50]) # this
is
>> very time consuming though
>
This comes to my mind:

as.vector(as.matrix(growthresumo[,3:50]))

but look up the help on stack() because it's a very powerful tool that
is aptly named (and might do everything you want).
>> Parcel <-
c("C9","S8"..."C9","S8") # 50 items
>
rep() could help with the above.
>> date < c("DATE1"...."DATE50")
>
paste() will help with this.
>> growthpermonth <- data.frame(Parcel, Date, growthvertical)
>
> Thank you very much!
Good luck with R!

Stephen