[R] jump in sequence

[Ben Fairbank]

Or perhaps

rep(4:6,3)+9*rep(0:2,rep(3,3)) 

with changes as necessary for longer sequences

Ben Fairbank


-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Adrian DUSA
Sent: Tuesday, January 30, 2007 8:29 AM
To: r-help at stat.math.ethz.ch
Subject: [R] jump in sequence

Dear list,

This should be a simple one, I just cannot see it.
I need to generate a sequence of the form:
4  5  6 13 14 15 22 23 24

That is: starting with 4, make a 3 numbers sequence, jump 6, then
another 3
and so on.
I can create a whole vector with:
myvec <- rep(rep(c(F, T, F), rep(3, 3)), 3)

Then see which are TRUE:
which(myvec)
[1]  4  5  6 13 14 15 22 23 24


I'd like to avoid creating the whole vector if possible; for very large
ones
it can be time consuming. There should be a way to only create the
proper
indexes...

Thanks for any hint,
Adrian

-- 
Adrian Dusa
Romanian Social Data Archive
1, Schitu Magureanu Bd
050025 Bucharest sector 5
Romania
Tel./Fax: +40 21 3126618 \
          +40 21 3120210 / int.101

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