R help - May 2006 - Automate concatenation?

I have this typical problem of joining a number of vectors with similar
names - a1, a2,..., a10 - which should be concatenated into one. Using
c(a1,a2,a3,a4,a5,a6,a,a8,a9,a10) naturally works, but I would like to do
it with less manual input. My attempts to use paste() gives a vector of
the vector names, see below. The question is how to do the the
concatenation? Any suggestions?

paste("a",1:10,sep="")

Robert

you need get(), look also at FAQ 7.21

a1 <- 1:3
a2 <- 4:5
a3 <- 6:10
a4 <- 11:20
a5 <- 21:25
#####################
lapply(paste("a", 1:5, sep = ""), get)

I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
     http://www.student.kuleuven.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "Robert Lundqvist" <Robert.Lundqvist at ltu.se>
To: <r-help at stat.math.ethz.ch>
Sent: Tuesday, May 30, 2006 2:07 PM
Subject: [R] Automate concatenation?

>I have this typical problem of joining a number of vectors with 
>similar
> names - a1, a2,..., a10 - which should be concatenated into one. 
> Using
> c(a1,a2,a3,a4,a5,a6,a,a8,a9,a10) naturally works, but I would like 
> to do
> it with less manual input. My attempts to use paste() gives a vector 
> of
> the vector names, see below. The question is how to do the the
> concatenation? Any suggestions?
>
> paste("a",1:10,sep="")
>
> Robert
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
> 

Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm

Robert Lundqvist <Robert.Lundqvist at ltu.se> writes:
> I have this typical problem of joining a number of vectors with similar
> names - a1, a2,..., a10 - which should be concatenated into one. Using
> c(a1,a2,a3,a4,a5,a6,a,a8,a9,a10) naturally works, but I would like to do
> it with less manual input. 
And less error-prone (where did the "7" go?)...
> My attempts to use paste() gives a vector of
> the vector names, see below. The question is how to do the the
> concatenation? Any suggestions?
> 
> paste("a",1:10,sep="")
I think this should work:

unlist(lapply( paste("a",1:10,sep=""), get))

(and of course, the usual sermon applies: You're likely better off
using a list of vectors rather than vectors with similar names.)

-- 
   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

On Tue, 30 May 2006, Robert Lundqvist wrote:
> I have this typical problem of joining a number of vectors with similar
> names - a1, a2,..., a10 - which should be concatenated into one. Using
> c(a1,a2,a3,a4,a5,a6,a,a8,a9,a10) naturally works, but I would like to do
> it with less manual input. My attempts to use paste() gives a vector of
> the vector names, see below. The question is how to do the the
> concatenation? Any suggestions?
>
> paste("a",1:10,sep="")
a1 <- c(5, 4)
a2 <- 2
a3 <- 6:9
cmd <- sprintf("c(%s)",
               paste("a", 1:3, sep = "", collapse = ",
"))
eval(parse(text = cmd))


----------------------------------------------------------
SIGSIG -- signature too long (core dumped)

Well, I like do.call():

puddy.tat <-
do.call("c",lapply(paste("a",1:10,sep=""),get))

			cheers,

				Rolf Turner
				rolf at math.unb.ca