Re: [R] Automate concatenation?
> "Paul" == Paul Roebuck <[EMAIL PROTECTED]>
> on Tue, 30 May 2006 16:04:14 -0500 (CDT) writes:
Paul> 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="")
Paul> a1 <- c(5, 4)
Paul> a2 <- 2
Paul> a3 <- 6:9
Paul> cmd <- sprintf("c(%s)",
Paul>paste("a", 1:3, sep = "", collapse = ", "))
Paul> eval(parse(text = cmd))
Executive Summary: "Try not to use eval(parse(text = * )) "
Excuse me, Paul,
but the other replies to this message had better answers. If you do
install.packages("fortunes")
library("fortunes")
fortune("answer is parse")
You get a very notable advise (by Thomas Lumley)
on why a solution using parse() very often ``stinks''.
In the present example and quite a few other ones, the much
better solution is to use get() [as the other replies in this
thread do].
In a recent private e-mail, Brian Ripley has reminded me of the
generic way to avoid eval(parse(text = * )) ,
namely via eval(substitute(f(A,B), list(A=.., B=..))
Martin Maechler, ETH Zurich
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Re: [R] Automate concatenation?
Well, I like do.call():
puddy.tat <- do.call("c",lapply(paste("a",1:10,sep=""),get))
cheers,
Rolf Turner
[EMAIL PROTECTED]
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Re: [R] Automate concatenation?
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)
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Re: [R] Automate concatenation?
Robert Lundqvist <[EMAIL PROTECTED]> 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 Øster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907
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Re: [R] Automate concatenation?
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" <[EMAIL PROTECTED]>
To:
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
>
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>
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