Re: [R] how to get the row name?

From: Antonio, Fabio Di Narzo <antonio.fabio_at_gmail.com>
Date: Tue 31 Jan 2006 - 08:30:11 EST

2006/1/30, Ionut Florescu <ifloresc@stevens.edu>:
>
> I don't know about rownames but
> x >= 0 gives you a vector of logical values True and false.
> If then you do
> c(1:length(x)) [x>=0]
> this gives the positions where the true happened, meaning your vector of
> values.

But also returns NA's, if present in 'X'. If you're really interested in indices of matched condition, consider using 'which': which(mydata$X>=0)
Anyway, if you're really interested in rownames instead of numerical indices, you have various options. For example: rownames(mydata)[which(mydata$X>=0)]
or, more compactly, as Chuck Cleland has suggested: rownames(subset(mydata, X >=0))

Antonio, Fabio Di Narzo.

> Chuck Cleland wrote:
> > rownames(subset(mydata, X >=0))
> >
> > ?rownames
> >
> > Leaf Sun wrote:
> >
> >> Hi R-listers,
> >>
> >> I have a simple question about a data frame.
> >>
> >> I sorted a data set by one of the variable in some condition (eg.
> X>=0), the followed is part of the achieved. I was wondering how can I get
> the row name, i. e. (1202, 2077 , 2328, 3341,... ) and save them as a
> vector. Thanks!
> >>
> >> Tag Species X Y Dbh3 Recr4 mort slope
> elevation aspect SA SR dist1 dist2 dist3
> >> 1202 19103 316 856.0 430.3 21 4 1 9.87 151.42
> 60.08 25.38 1.02 0.2236068 0.7211103 1.3601471
> >> 2077 29893 316 935.4 482.7 28 4 1 5.66 137.28
> 13.86 25.14 1.01 0.6403124 0.8944272 1.0630146
> >> 2328 32989 316 910.7 301.5 12 4 1 8.07 137.69
> 86.16 25.26 1.01 0.3000000 1.2806248 1.3038405
> >> 3341 45198 316 975.2 2.4 144 4 1 2.95 121.10
> 173.60 0.00 0.00 0.5656854 1.2727922 1.3416408
> >> ...
> >>
> >> Regards,
> >>
> >> Leaf
> >>
> >>
> >>
> >>
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> >
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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Tue Jan 31 08:58:42 2006

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