[R] Counting indexes

[Peter Alspach]

Tena koe Robin

See rle - it doesn't do exactly what you want but by looking at the code
(simply enter rle without brackets) you should be able to get there.

HTH ...

Peter Alspach

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Robin Jeffries
> Sent: Wednesday, 26 May 2010 4:15 p.m.
> To: r-help at r-project.org
> Subject: [R] Counting indexes
> 
> Hallo!
> 
> I have a vector of ID's like so,
> id <- c(1,2,2,3,3,3,4,5,5)
> 
> I would like to create a [start,stop] pair of vectors that index the
> first
> and last observation per ID.
> 
> For the ID list above, it would look like
> 1 1
> 2 3
> 4 6
> 7 7
> 8 9
> 
> I haven't worked with indexes/data manipulation much in R, so any
> pointers
> would be helpful.
> 
> Many thanks!
> 
> ~~~~~~~~~~~~~~~~~~~
> -Robin Jeffries
> Dr.P.H. Candidate in Biostatistics
> UCLA School of Public Health
> rjeffries at ucla.edu
> 530-624-0428
> 
> 	[[alternative HTML version deleted]]
> 
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