R help - Oct 2009 - field index given name.

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





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Hi Phil
Try the following
> which(names(iris)=='Species')
[1] 5

HTH
Schalk Heunis

On Mon, Oct 12, 2009 at 8:53 AM, tdm <philb@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.
>
> ______________________________________________
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