Re: [R] Column renaming

From: Chip Barnaby <cbarnaby_at_wrightsoft.com>
Date: Mon, 05 May 2008 11:26:46 -0400

Peter,
My method seems to work, see below. Is there some reason it might not work in general? This is the tersest way I have found to rename, but it seems awkward, given that names( X) is repeated.

Chip Barnaby


 > head( airquality)
   Ozone Solar.R Wind Temp Month Day

1    41     190  7.4   67     5   1
2    36     118  8.0   72     5   2
3    12     149 12.6   74     5   3
4    18     313 11.5   62     5   4
5    NA      NA 14.3   56     5   5
6    28      NA 14.9   66     5   6
 >

 > names( airquality)[names( airquality)=="Ozone"]<-"O3"  > head( airquality)
   O3 Solar.R Wind Temp Month Day
1 41     190  7.4   67     5   1
2 36     118  8.0   72     5   2
3 12     149 12.6   74     5   3
4 18     313 11.5   62     5   4
5 NA      NA 14.3   56     5   5
6 28      NA 14.9   66     5   6

 >

At 11:19 AM 5/5/2008, Peter Dalgaard wrote:
>Chip Barnaby wrote:
> > Dear all,
> >
> > Is there a less cumbersome way to rename a column by name (as opposed
> > to index) than --
> >
> > names( X)[ names[ X] == "bob"]<-"sue"
> >
> > ?
>Not that I know of (notwithstanding that your code doesn't quite work as
>it stands...). You might have thought that this would work, but it
>obviously does not:
>
> > names(airquality["Ozone"]) <- "O3"
> > head(airquality)
> Ozone Solar.R Wind Temp Month Day
>1 41 190 7.4 67 5 1
>2 36 118 8.0 72 5 2
>3 12 149 12.6 74 5 3
>4 18 313 11.5 62 5 4
>5 NA NA 14.3 56 5 5
>6 28 NA 14.9 66 5 6
>
>(This is probably a design decision. In the same vein,
>
>airquality[6] <- data.frame(foo=1:153)
>
>will not change the name of column 6. It might be preferable if it did,
>from the conceptual point of view, but it is one of those things where I
>suspect that the world comes tumbling down if you try to change the
>behaviour...)
>
> >
> > A semi-related question: how does one get the index of a column by
> > name, something along the lines of col.index( X, "sue") ?
> >
>match("sue", names(X))
>
>--
> O__ ---- Peter Dalgaard ˜ster Farimagsgade 5, Entr.B
> c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
> (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
>~~~~~~~~~~ - (p.dalgaard_at_biostat.ku.dk) FAX: (+45) 35327907


Chip Barnaby                   cbarnaby_at_wrightsoft.com
Vice President of Research
Wrightsoft Corp.               781-862-8719 x118 voice
131 Hartwell Ave               781-861-2058 fax
Lexington, MA 02421         www.wrightsoft.com
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