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: <[EMAIL PROTECTED]> To: <[email protected]> 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. > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
