[R] help with vector construction

[Greg Snow]

One approach is to use the fact that vectors are automatically
replicated to the correct length when subscripting, so you can do
something like:

> my.matrix[ c(FALSE,TRUE,FALSE), 3 ] 

To get every 3rd element starting at the 2nd element, and the 3rd
column.

Hope this helps,


-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at intermountainmail.org
(801) 408-8111
 
 

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Juan 
> Pablo Fededa
> Sent: Thursday, July 05, 2007 11:30 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] help with vector construction
> 
> Hi all,
> 
> I want to make a vector with the third column of a matrix, 
> but only for the
> 2+3n rows of the matrix, with n being an entire number from 0 
> to a million.
> How can I do that in an easy way?
> Thanks in advance,
> 
> Juan Pablo
> 
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> 
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