Thanks - would never have guessed that. I eventually got the following to do
what I want...
> colprob <- array(dim=NCOL(iris))
> for(i in 1:NCOL(iris)){
+ colprob[i]=
+ ifelse(names(iris)[i] == 'Species',1,0.5)
+ }
> colprob
[1] 0.5 0.5 0.5 0.5 1.0
Schalk Heunis-2 wrote:
>
> Hi Phil
> Try the following
>> which(names(iris)=='Species')
> [1] 5
>
> HTH
> Schalk Heunis
>
> On Mon, Oct 12, 2009 at 8:53 AM, tdm <ph...@philbrierley.com> wrote:
>
>>
>> Hi,
>>
>> How do I access the index number of a field given I only know the field
>> name?
>>
>> eg - I want to set the probability of the field 'species' higher than the
>> other fields to use in sampling.
>>
>> > colprob <- array(dim=NCOL(iris))
>> > for(i in 1:NCOL(iris)){colprob[i]=0.5}
>> > colprob[iris$species] = 1 #this doesn't work
>> > colprob
>> [1] 0.5 0.5 0.5 0.5 0.5
>>
>>
>>
>>
>>
>> --
>> View this message in context:
>> http://www.nabble.com/field-index-given-name.-tp25851216p25851216.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> R-help@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>
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