[R] Basic matematical functions with NAs

roger bos roger.bos at gmail.com
Tue May 24 16:36:25 CEST 2005


Simple, all those functions, such as sum(), colSums(), colMeans(),
etc. have an argument called na.rm which you can set to TRUE to remove
NAs.

so try something like sum(X, na.rm=TRUE)


HTH,

Roger



On 5/24/05, Paulo Brando <pmbrando at ipam.org.br> wrote:
> Dear All,
> 
> I've tried to sum columns -- different species of flowers, fruits plus twigs -- with NAs to get litterfall/trap, and then after use litterfall to calculate production (litterfall (grams)/ hectare/ day. But R 'sees' litterfall/trap as a string.
> 
> My question: How to use basic mathematical functions to deal with NAs in data management.
> 
> Example (as you can note I have many missing values -- no fruit  fell in the trap.
> 
> 
>      area ponto date pseco psaco pliquido florg1 flor1 florg2 flor2 florg3 flor3 frutog1 fruto1 frutog2 fruto2 frutog3 fruto3 frutog4 fruto4 frutog5 fruto5 frutog6 fruto6 frutog7 fruto7 frutog8 fruto8 twigs
>      A A 1 38233 17.7 1.6 7.1 0.266 1
>      A AA 1 38233 12.5 8.7 3.8
>      A AB 1 38233 13.9 1.7 3.2       0.421 3
>      A B 1 38233 12.1 1.6 1.5       0.248 2 0.435 7 0.16 1
>      A BORDA 1 38233
>      A C 1 38233 15.6 1.7 4.9       0.374 2 0.298 3 0.231 1
>      A F 1 38233 14 1.5 3.5 0.366 45     0.153 1 0.15 1
> 
> 
> 
> Paulo Brando
> Inst. de Pesquisa Ambiental da Amazônia (IPAM)
> Rua Rui Barbosa,136.
> 68.005.080 Santarém, PA, Brazil.
> Fone/Fax ++ 55 93 522 5538
> www.ipam.org.br
>        [[alternative HTML version deleted]]
> 
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