Dear all, I have got a question for generating repeats of a vector's elements. Please don't hesitate to email me back and say that it is very easy although I can't find a method to solve it. If I have a n-vector b, whose elements are b[1], b[2], ..., b[n], how can I generate such a vector b[1], b[1], b[2], b[1], b[2], b[3], b[1], b[2], b[3], b[4], ......, b[1], b[2], ..., b[n] which contains n(n+1)/2 elements. Thanks very much. Regards Chaofeng Kou [[alternative HTML version deleted]]
I would do it like this but I'm curious to see whether it can be easier
solved :-)
b <- c(1:10)
vector_list <- lapply(1:length(b), FUN = function(x) { b[1:x] }))
(for everything in a large vector just apply "unlist" to the
"vector_list")
Antje
Chaofeng Kou schrieb:> Dear all,
>
> I have got a question for generating repeats of a vector's elements.
> Please don't hesitate to email me back and say that it is very easy
> although I can't find a method to solve it.
>
> If I have a n-vector b, whose elements are b[1], b[2], ..., b[n], how
> can I generate such a vector
>
> b[1], b[1], b[2], b[1], b[2], b[3], b[1], b[2], b[3], b[4],
> ......, b[1], b[2], ..., b[n]
>
> which contains n(n+1)/2 elements.
>
> Thanks very much.
>
> Regards
> Chaofeng Kou
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org 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.
>
try this:
b <- rnorm(4)
ind <- unlist(lapply(seq_along(b), seq_len))
b
b[ind]
I hope it helps.
Best,
Dimitris
----
Dimitris Rizopoulos
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://perswww.kuleuven.be/dimitris_rizopoulos/
----- Original Message -----
From: "Chaofeng Kou" <kouchaofeng at gmail.com>
To: <r-help at r-project.org>
Sent: Friday, July 18, 2008 2:21 PM
Subject: [R] generate repeats of a vector's elements
> Dear all,
>
> I have got a question for generating repeats of a vector's elements.
> Please don't hesitate to email me back and say that it is very easy
> although I can't find a method to solve it.
>
> If I have a n-vector b, whose elements are b[1], b[2], ..., b[n],
> how
> can I generate such a vector
>
> b[1], b[1], b[2], b[1], b[2], b[3], b[1], b[2], b[3], b[4],
> ......, b[1], b[2], ..., b[n]
>
> which contains n(n+1)/2 elements.
>
> Thanks very much.
>
> Regards
> Chaofeng Kou
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org 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.
>
Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm