# Re: [R] peak finding

From: Research Scholar <thesis1977_at_gmail.com>
Date: Mon, 24 Mar 2008 23:23:57 -0400

Hi
Thanks for replying. I meant x[4] is the start of a peak shape and x[14] is the end of that peak and x[9] is the maxima of the peak. Thanks,
John

On Mon, Mar 24, 2008 at 11:09 PM, <Bill.Venables_at_csiro.au> wrote:

> It's hard to see how positions 4 and 14 correspond to 'peaks', they look
> like troughs to me. So perhaps this is what you mean:
>
> > x <- c(14,15,12,11,12,13,14,15,16,15,14,13,12,11,14,12)
>
> > y <- which(x == min(x))
> > y
> [1] 4 14
>
> as a function:
>
> somefunction <- function(x) which(x == min(x))
>
>
> Bill Venables
> CSIRO Laboratories
> PO Box 120, Cleveland, 4163
> AUSTRALIA
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>
> -----Original Message-----
> From: r-help-bounces_at_r-project.org [mailto:r-help-bounces_at_r-project.org]
> On Behalf Of Research Scholar
> Sent: Tuesday, 25 March 2008 12:54 PM
> To: r-help_at_r-project.org
> Subject: [R] peak finding
>
> Hi all
> Is there a function that can find the start and end position of peaks
> in a
> set of numbers.
> eg.
> x <- c(14,15,12,11,12,13,14,15,16,15,14,13,12,11,14,12)
> y <- somefunction(x)
>
> y
> 4 14
>
>
> Thanks
> John
>
> [[alternative HTML version deleted]]
>
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>
>

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