From: Dimitris Rizopoulos <dimitris.rizopoulos_at_med.kuleuven.be>

Date: Mon 13 Feb 2006 - 23:55:11 EST

ind <- which.min(abs(mat[, 1] - val))

mat

mat[ind, ]

Dimitris Rizopoulos

Ph.D. Student

Biostatistical Centre

School of Public Health

Catholic University of Leuven

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Mon Feb 13 23:58:35 2006

Date: Mon 13 Feb 2006 - 23:55:11 EST

maybe something like this could be of help:

mat <- matrix(rnorm(20), 10, 2)

val <- -0.6523

###################

ind <- which.min(abs(mat[, 1] - val))

mat

mat[ind, ]

Best,

Dimitris

Dimitris Rizopoulos

Ph.D. Student

Biostatistical Centre

School of Public Health

Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium

Tel: +32/(0)16/336899 Fax: +32/(0)16/337015 Web: http://www.med.kuleuven.be/biostat/ http://www.student.kuleuven.be/~m0390867/dimitris.htm

- Original Message ----- From: <Ita.Cirovic-Donev@hypo-alpe-adria.com> To: <r-help@stat.math.ethz.ch> Sent: Monday, February 13, 2006 1:30 PM Subject: [R] search algorithm

*>
**>
**>
**>
**> Hi!
**>
*

> I have a problem of finding a specific value in a column. For

*> example, I
**> have a matrix with say 2 columns
**>
**> X Y
**> 1 -2.0341602 9.036689e-05
**> 2 -1.4287230 1.807338e-04
**> 3 -1.1194402 2.711007e-04
**> 4 -1.0327582 3.614676e-04
**> 5 -0.8130556 4.518344e-04
**> 6 -0.7138212 5.422013e-04
**> 7 -0.6634425 6.325682e-04
**> 8 -0.6512083 7.229351e-04
**> 9 -0.6176286 8.133020e-04
**> 10 -0.5897241 9.036689e-04
**>
**> Now if I have some value of x=-0.6523. I need to find a value in the
**> X
**> column that is the closest to my value of x then read off the row
**> number
**> and then take the corresponding value in column Y. What I am not
**> sure is
**> how to do the first search where I would search by decimal places
**> and take
**> the smallest absolute distance between the numbers. For example if
**> he finds
**> the first value which is correct in this case - and then 0 and then
**> 6 and
**> then 5 but now there is no 2 for that specific decimal place so he
**> would
**> calculate the distance between the one before and the one after and
**> see
**> which one is smaller. For that which is smaller would be the final X
**> value.
**> Can someone please give me a hint on how to proceed. Thanks.
**>
**> ______________________________________________
**> R-help@stat.math.ethz.ch mailing list
**> https://stat.ethz.ch/mailman/listinfo/r-help
**> PLEASE do read the posting guide!
**> http://www.R-project.org/posting-guide.html
**>
*

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R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Mon Feb 13 23:58:35 2006

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