Proba( Ut+2=1 / ((Ut+1==1) && (Ut==1))) ?

maybe something like this:

x <- sample(c(1, -1), 100, TRUE)
y <- rle(x)
##
ind1 <- y$length[y$value == 1]
sum(ind1[ind1 > 2] - 2)
ind2 <- y$length[y$value == -1]
##
sum(ind1[ind1 > 2] - 2)


could be helpful.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/16/336899
Fax: +32/16/337015
Web: http://www.med.kuleuven.ac.be/biostat/
     http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "vincent" <vincent at 7d4.com>
To: <r-help at stat.math.ethz.ch>
Sent: Monday, April 25, 2005 6:03 PM
Subject: [R] Proba( Ut+2=1 / ((Ut+1==1) && (Ut==1))) ?

Dear all,

First I apologize if my question is quite simple,
but i'm very newbie with R.

I have vectors of the form v = c(1,1,-1,-1,-1,1,1,1,1,-1,1)
(longer than this one of course).
The elements are only +1 or -1.

I would like to calculate :
- the frequencies of -1 occurences after 2 consecutives -1
- the frequencies of +1 occurences after 2 consecutives +1

It looks probably something like :
Proba( Ut+2=1 / ((Ut+1==1) && (Ut==1)))

could someone please give me a little hint about how
i should/could begin to proceed ?

Thanks
(Thanks also to the R creators/contributors, this soft
seems really great !)

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