[R] R Equivalent to matlab's find() command?

[Prof Brian D Ripley]

On Thu, 8 Jun 2000, Stephen Eglen wrote:

> hi,
> 
> Just a very simple question: is there an R equivalent to the matlab
> command find(X) which returns the indices of vector X that store
> non-zero elements?
> 
> e.g.
> > find( [1 0 0 1 0])
> ans =
> 
>   1  4
> 
> so, in R, how do I do:
> 
> ans <- rfind( c(1,0,0,1,0))
> 
> so that ans is the vector c(1,4)


rfind <- function(x) seq(along=x)[x != 0]

It's a peculiar name, though ....

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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