From: Bert Gunter <gunter.berton_at_gene.com>

Date: Sat, 18 Aug 2012 09:14:41 -0700

Date: Sat, 18 Aug 2012 09:14:41 -0700

Or to expand just a hair on Joshua's suggestion, is the following what you want:

*> x <- 1:10
**> names(x) <- letters[1:10]
**> x
*

a b c d e f g h i j

1 2 3 4 5 6 7 8 9 10

*> df <- data.frame(x=x,y=LETTERS[1:10],row.names=names(x))
**> df
*

x y

a 1 A

b 2 B

c 3 C

d 4 D

e 5 E

f 6 F

g 7 G

h 8 H

i 9 I

j 10 J

*> y <- t(df[,1,drop=FALSE])[1,]
**> y
*

a b c d e f g h i j

1 2 3 4 5 6 7 8 9 10

*> identical(x,y)
*

**[1] TRUE
**
Cheers,

Bert

On Sat, Aug 18, 2012 at 8:16 AM, Joshua Ulrich <josh.m.ulrich_at_gmail.com> wrote:

> I don't know if this is better, but it's the most obvious/shortest I

*> could come up with. Transpose the data.frame column to a 'row' vector
**> and drop the dimensions.
**>
**> R> identical(nv, drop(t(df)))
**> [1] TRUE
**>
**> Best,
**> --
**> Joshua Ulrich | about.me/joshuaulrich
**> FOSS Trading | www.fosstrading.com
**>
**>
**> On Sat, Aug 18, 2012 at 10:03 AM, Martin Maechler
**> <maechler_at_stat.math.ethz.ch> wrote:
**>> Today, I was looking for an elegant (and efficient) way
**>> to get a named (atomic) vector by selecting one column of a data frame.
**>> Of course, the vector names must be the rownames of the data frame.
**>>
**>> Ok, here is the quiz, I know one quite "cute"/"slick" answer, but was
**>> wondering if there are obvious better ones, and
**>> also if this should not become more idiomatic (hence "R-devel"):
**>>
**>> Consider this toy example, where the dataframe already has only
**>> one column :
**>>
**>>> nv <- c(a=1, d=17, e=101); nv
**>> a d e
**>> 1 17 101
**>>
**>>> df <- as.data.frame(cbind(VAR = nv)); df
**>> VAR
**>> a 1
**>> d 17
**>> e 101
**>>
**>> Now how, can I get 'nv' back from 'df' ? I.e., how to get
**>>
**>>> identical(nv, .......)
**>> [1] TRUE
**>>
**>> where ...... only uses 'df' (and no non-standard R packages)?
**>>
**>> As said, I know a simple solution (*), but I'm sure it is not
**>> obvious to most R users and probably not even to the majority of
**>> R-devel readers... OTOH, people like Bill Dunlap will not take
**>> long to provide it or a better one.
**>>
**>> (*) In my solution, the above '.......' consists of 17 letters.
**>> I'll post it later today (CEST time) ... or confirm
**>> that someone else has done so.
**>>
**>> Martin
**>>
**>> ______________________________________________
**>> R-devel_at_r-project.org mailing list
**>> https://stat.ethz.ch/mailman/listinfo/r-devel
**>
**> ______________________________________________
**> R-devel_at_r-project.org mailing list
**> https://stat.ethz.ch/mailman/listinfo/r-devel
*

-- Bert Gunter Genentech Nonclinical Biostatistics Internal Contact Info: Phone: 467-7374 Website: http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm ______________________________________________ R-devel_at_r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-develReceived on Sun 19 Aug 2012 - 13:32:12 GMT

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