Message-ID: <3C1B003A-E038-40A1-B46C-8EA02FD7A6E1@imperial.ac.uk>
Date: 2013-11-11T13:01:03Z
From: Federico Calboli
Subject: repeating values in an index two by two
In-Reply-To: <CABcwgRQaB56EeGZF1_FpK-Dv1LToK3-WA6UshdTL+3Q8f1QjLA@mail.gmail.com>
Hi,
first off, thanks for the suggestion. I managed to solve it by doing:
IND = rep(c(T,T,F,F), 5)
X = rep(NA, 20)
X[IND] = 1:10
X[!IND] = 1:10
which avoids any function -- I think mapply, apply etc call a for loop internally, which I'd rather avoid.
BW
F
On 11 Nov 2013, at 12:35, andrija djurovic <djandrija at gmail.com> wrote:
> Hi. Here are two approaches:
>
> c(mapply(function(x,y) rep(c(x,y), 2), (1:10)[c(T,F)], (1:10)[c(F,T)]))
>
> c(tapply(1:10, rep(1:(10/2), each=2), rep, 2), recursive=T)
>
> Andrija
>
>
>
>
>
> On Mon, Nov 11, 2013 at 1:11 PM, Federico Calboli <f.calboli at imperial.ac.uk> wrote:
> Hi All,
>
> I am trying to create an index that returns something like
>
> 1,2,1,2,3,4,3,4,5,6,5,6,7,8,7,8
>
> and so on and so forth until a predetermined value (which is obviously even). I am trying very hard to avoid for loops or for loops front ends.
>
> I'd be obliged if anybody could offer a suggestion.
>
> BW
>
> F
>
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