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Adrian DUSA

2007-Jan-30 14:29 UTC

[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

Peter Dalgaard

2007-Jan-30 14:38 UTC

head link

[R] jump in sequence

Adrian DUSA wrote:> 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
>   Is this it?
> as.vector(outer(0:2,seq(4,22,9),"+"))[1]  4  5  6 13 14 15 22 23 24

-- 
   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

Benilton Carvalho

2007-Jan-30 14:43 UTC

head link

[R] jump in sequence

is it sth like:

as.integer(sapply(seq(4, 22, by=9), seq, length.out=3))

you're looking for?

b

On Jan 30, 2007, at 9:29 AM, Adrian DUSA wrote:
> 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
>
> ______________________________________________
> 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
> and provide commented, minimal, self-contained, reproducible code.

Martin Becker

2007-Jan-30 14:46 UTC

head link

[R] jump in sequence

Adrian DUSA wrote:> 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...
>
>   Maybe:

n=10
3+rep(1:3,times=n)+9*rep(0:(n-1),each=3)
> Thanks for any hint,
> Adrian
>
>   
Regards,
  Martin

Adrian Dusa

2007-Jan-30 14:46 UTC

head link

[R] jump in sequence

On Tuesday 30 January 2007 16:38, Peter Dalgaard wrote:> >[...snip...]
> Is this it?
>
> > as.vector(outer(0:2,seq(4,22,9),"+"))
>
> [1]  4  5  6 13 14 15 22 23 24
Indeed it is :))
Thanks,
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

Robin Hankin

2007-Jan-30 15:05 UTC

head link

[R] jump in sequence

> f <- function(n){as.vector(sweep(matrix(4:6,nrow=3,ncol=n),2,seq (from=0,by=9,len=n),"+"))}
 > f(10)
[1]  4  5  6 13 14 15 22 23 24 31 32 33 40 41 42 49 50 51 58 59 60 67  
68 69 76 77 78 85 86 87
 >

HTH

rksh


On 30 Jan 2007, at 14:29, Adrian DUSA wrote:
> 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
>
> ______________________________________________
> 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
> and provide commented, minimal, self-contained, reproducible code.
--
Robin Hankin
Uncertainty Analyst
National Oceanography Centre, Southampton
European Way, Southampton SO14 3ZH, UK
  tel  023-8059-7743

Ben Fairbank

2007-Jan-30 15:38 UTC

head link

[R] jump in sequence

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

______________________________________________
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
and provide commented, minimal, self-contained, reproducible code.

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