[R] Column renaming

[Chip Barnaby]

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             Øster 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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