thanks a lot to all your help and quick response on
this small problem I had.
It is really appreciated..
ap
ind <- which(X > 0
& c(X[-1],0) > 200)[1] # returns NA if condition not
satisfied
X[ind +
0:1]
# so is NA if condition not
satisfied
From:
s-news-owner@lists.biostat.wustl.edu
[mailto:s-news-owner@lists.biostat.wustl.edu] On Behalf Of Mario Cortina
Borja
Sent: Thursday, July 07,
2005 1:55 AM
To: Potgieter,
Andries B
Cc:
s-news@lists.biostat.wustl.edu
Subject: Re: [S] Find first consecutive
pair in vector
>From: "Potgieter, Andries B"
<Andries.Potgieter@dpi.qld.gov.au>
>To:
s-news@lists.biostat.wustl.edu
>Date: Thu, 7 Jul 2005 17:13:58 +1000
>Thread-Topic: Find first consecutive pair in vector
>Thread-Index: AcWBiO1/Zpzj19LrRYWOe5KJqHkyfQAAL5/QAE5BvZA=
>Dear
s-list
>I want to find the
first consecutive pair with the first value >0 and the second value > 200
in the following vector:
>X
<- c( 204, -24, -33, 433,
-1123, 565, 366, -494,
261, 205, 270, 201)
>So in this case
index 6 and 7 will be the first event and 9,10; 10,11 and 11,12 the others. I
want only to select the first time this condition occurs in the
vector
>Any ideas in how to do it the easy way?
>Thanks
>Andries
Dear Andries,
A function that does that is:
find1<-
function(X, b1 = 0, b2 = 200)
{
s1
<- 1:(length(X) - 1)
s2
<- s1 + 1
res1
<- s1[X[s1] > b1 & X[s2] > b2][1]
c(res1,
res1 + 1)
}
Best wishes,
Mario
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