Thanks. the approxfun command works great --matches exactly with computing each point-to-point slope
Eric ----- Original Message ----- From: jim holtman To: Eric C. Jennings Cc: R-help Sent: Saturday, February 25, 2006 9:27 PM Subject: Re: [R] how to get f(x)=___ from a piecwise function ?approxfun > x<- c(-100.4, 32.0, 99.8, 200.2, 300.6, 399.8, 500.0, 600.0, 699.6, 799.6, + 899.8) > y<- c(0.4, 0.0, 0.2, -0.2, -0.6, 0.2, 0.0, 0.0, 0.4, 0.4, 0.2) > x.f <- approxfun(x,y) > x.f(356) [1] -0.1532258 On 2/25/06, Eric C. Jennings <[EMAIL PROTECTED]> wrote: >From actual real-world readings, I have two vectors: x<- c(-100.4, 32.0, 99.8, 200.2, 300.6, 399.8, 500.0, 600.0, 699.6, 799.6, 899.8) y<- c(0.4, 0.0, 0.2, -0.2, -0.6, 0.2, 0.0, 0.0, 0.4, 0.4, 0.2) which, in the usual way constitute a continuous piecewise function. What I want to do is find an easy method to get at f(x) for some x I have NOT specified in the above vector. For example I want f(356). I have already put the time and effort in to write a program to compute this by breaking the function into the various pieces and computing the slopes of the individual lines etc. etc. I am just looking to find an easier method. Thank you for your help. Eric ______________________________________________ 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 -- Jim Holtman Cincinnati, OH +1 513 646 9390 What the problem you are trying to solve? [[alternative HTML version deleted]] ______________________________________________ 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