Tong you need to use apply(). The second argument specifies whether you want to work with rows or columns. The point of this is that min() and max() operate on vectors and give a single value, and you want to "apply" this function to all rows or all columns:
> a <- matrix(rnorm(30),5,6) > apply(a,2,max) [1] 2.6413241 0.9842076 1.7989560 0.6999855 2.0542201 0.1162821 > apply(a,1,max) [1] 1.1771370 0.9811693 2.6413241 0.9842076 2.0542201 > HTH rksh On 6 Sep 2006, at 09:37, Tong Wang wrote: > Hi, > Is there a function which operates on a matrix and return a > vector of min/max of each rol/col ? > say, X= 2, 1 > 3, 4 > min.col(X)=c(2,1) > > thanks a lot. > > tong > > ______________________________________________ > 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 > and provide commented, minimal, self-contained, reproducible code. -- Robin Hankin Uncertainty Analyst National Oceanography Centre, Southampton European Way, Southampton SO14 3ZH, UK tel 023-8059-7743 ______________________________________________ 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 and provide commented, minimal, self-contained, reproducible code.
