[R] missing values

[Ulrich Leopold]

Renaud Lancelot wrote:
> tapply(lsk0t50$Pox2, lsk0t50$ProfN, function(x) sum(x[!is.na(x)]) )

Also for your suggestion I get the same strange result. It seems that the 
following columns interfere with the variable(Pox2) column because the 
missing values are omitted, excluded etc.

So maybe I am using the wrong command by using tapply?

I have a data object with several columns and would like to sum one column 
by a factor given in antother column but omitting, excluding the NAs.

Regards, Ulrich


> Best,
> 
> Renaud
> 
> Ulrich Leopold wrote:
> 
>>Dear list,
>>
>>how can I exclude the missing values in the following example:
>>
>>tapply(lsk0t50$Pox2, lsk0t50$ProfN, sum)
>>
>>I tried:
>>
>>tapply(lsk0t50$Pox2, lsk0t50$ProfN, sum, Fun=is.na(lsk0t50$Pox2))
>>
>>But it returns a lot of missing values in the result. Instead the missing
>>values in the variable should not be taken into account. So that I get only
>>a NA as result if there are only NAs for the corresponding factor.
>>
>>Any idea how this can be achieved?
>>
>>Thanks,
>>Ulrich
>>--
>>__________________________________________________
>>
>>Ulrich Leopold MSc.
>>
>>Department of Physical Geography
>>Institute for Biodiversity and Ecosystem Dynamics
>>Faculty of Science
>>University of Amsterdam
>>Nieuwe Achtergracht 166
>>NL-1018WV Amsterdam
>>
>>Phone: +31-(0)20-525-7456 (7451 Secretary)
>>Fax:   +31-(0)20-525-7431
>>Email: uleopold at science.uva.nl
>>http://www.frw.uva.nl/soil/Welcome.html
>>
>>Check us also out at:
>>Netherlands Centre for Geo-ecological Research
>>http://www.frw.uva.nl/icg
>>
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> 
> 


-- 
__________________________________________________

Ulrich Leopold MSc.

Department of Physical Geography
Institute for Biodiversity and Ecosystem Dynamics
Faculty of Science
University of Amsterdam
Nieuwe Achtergracht 166
NL-1018WV Amsterdam

Phone: +31-(0)20-525-7456 (7451 Secretary)
Fax:   +31-(0)20-525-7431
Email: uleopold at science.uva.nl
http://www.frw.uva.nl/soil/Welcome.html

Check us also out at:
Netherlands Centre for Geo-ecological Research
http://www.frw.uva.nl/icg



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