[R] Getting the index of specific quantiles
Sarah Goslee
sarah.goslee at gmail.com
Tue Nov 22 15:18:15 CET 2016
Here's how to get one:
x <- c(9,9,1,3,2,7,6,10,5,6)
> which.min(abs(x - quantile(x, .25)))
[1] 4
And here's one of the various ways to get the entire set:
> xq <- quantile(x)
> sapply(xq, function(y)which.min(abs(x - y)))
0% 25% 50% 75% 100%
3 4 7 1 8
Sarah
On Tue, Nov 22, 2016 at 7:21 AM, Matteo Richiardi
<matteo.richiardi at gmail.com> wrote:
> Dear R-users,
> a very easy one for you, I guess. I need to extract the indexes of the
> elements corresponding to different quantiles of a vector. When a
> quantile is an interpolation between two adjacent values, I need the
> index of the value which is closer (the lower value - or the higher
> value for what matters - in case the quantile is exactly half way
> through).
>
> This is an example.
>
>> x <- c(9,9,1,3,2,7,6,10,5,6)
>> quantile(x)
> 0% 25% 50% 75% 100%
> 1.0 3.5 6.0 8.5 10.0
>
> What I need is a vector 'index' which looks like
>
>> index
> 3 4 7 1 8
>
> Many thanks for your help ! Matteo
>
--
Sarah Goslee
http://www.functionaldiversity.org
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