Hi there,

Is this what you want?

your.number=5.43

# For a vector
x=c(1,2,4,3,2,5,6,7,5.42,6)
which.min(abs(x-your.number))
[1] 9

# For a matrix
set.seed(123)
X=matrix(rpois(100,4.5),ncol=10)
apply(X,2,function(x) which.min(abs(x-your.number)))
 [1] 9 3 2 3 2 5 1 2 2 2


HTH,

Jorge


On Wed, Jul 9, 2008 at 11:28 AM, R_Learner <sschiang8@gmail.com> wrote:

>
> I have a long list of numbers [3.4,5.4,3.67,....], and I basically want to
> find the index of the number closest to this number that I have, let's say
> 5.43. How would I do this without writing a for loop (I have to do this
> many
> times for several lists)? Is there a "lookup" function in R?
>
> Thanks!
> --
> View this message in context:
> http://www.nabble.com/Find-the-closest-value-in-a-list-or-matrix-tp18363290p18363290.html
> Sent from the R help mailing list archive at Nabble.com.
>
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