[R] Vector manipulations

[Jonathan P Daily]

Is this what you want? I don't know what your v looks like, but this won't 
work if there are cases in which v won't sum to exactly x.

x <- 20
v <- sample(0:1, 100, T)

w <- v[1:which(cumsum(v)==x)]
--------------------------------------
Jonathan P. Daily
Technician - USGS Leetown Science Center
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"Is the room still a room when its empty? Does the room,
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     - Jubal Early, Firefly

r-help-bounces at r-project.org wrote on 03/02/2011 10:42:12 AM:

> [image removed] 
> 
> [R] Vector manipulations
> 
> Benjamin Hartley 
> 
> to:
> 
> r-help
> 
> 03/02/2011 11:08 AM
> 
> Sent by:
> 
> r-help-bounces at r-project.org
> 
> I have a question regarding the most efficient way to select a substring 
of
> a vector:
> 
> I have a vector of value v, and I want to select a subspace of this 
vector
> called w such that:
> 
> w=v[1:n]
> 
> where
> 
> sum(w) = x
> 
> I am interested in what you thing would be the most efficient way to do 
this
> - I would like to avoid slowing down my simulations as much as possible.
> 
> Thank you very much for any help that anyone is able to give.
> 
>    [[alternative HTML version deleted]]
> 
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