Actually, this may just be a typo in your first post, but if you actually want to do this calculation:
(array[,,1] + array[,,2] + array[,,3] + array[,,4] + array[,,5] + array[,,6] + array[,,7] + array[,,8]) / 8 Wouldn't this work? apply(array,3,sum)/dim(array)[3] On Wed, Oct 5, 2011 at 4:22 PM, R. Michael Weylandt <michael.weyla...@gmail.com> wrote: > Didn't three of us give you a function (in various flavors) that would > do the mean for variable inputs, reading them from a list? (Though > David's was admittedly much cooler than mine!) > > Anyways, look into parse(text=do) with eval() if you want to go the > string route. > > Michael > > On Wed, Oct 5, 2011 at 4:14 PM, Martin Batholdy <batho...@googlemail.com> > wrote: >> Dear R-group, >> >> >> is there a way to perform calculations that are defined in a string format? >> >> >> for example I have different variables: >> >> x1 <- 3 >> x2 <- 1 >> x4 <- 1 >> >> and a string-variable: >> >> do <- 'x1 + x2 + x3' >> >> >> Is there any way to perform what the variable 'do'-describes >> (just like the formula-element but more elemental)? >> >> >> >> Perhaps my idea to solve my problem is a little bit strange. >> >> >> My general problem is, that I have to do arithmetics for which there seems >> to be no function available that I can apply in order to be more flexible. >> >> >> To be precise, I have to add up three dimensional arrays. >> >> I can do that like this (as someone suggested on this help-list – thanks for >> that!): >> >> (array[,,1] + array[,,2] + array[,,3]) / 3 >> >> >> However in my case it can happen that at some point, I don't have to add 3 >> but 8 'array-slices' >> (or 10 or x). >> >> And I don't want to manually expand the above statement to: >> >> (array[,,1] + array[,,2] + array[,,3] + array[,,4] + array[,,5] + array[,,6] >> + array[,,7] + array[,,8]) / 8 >> >> (ok, now I have done it ;) >> >> >> >> So, my thinking was that I can easily expand and change a string (with the >> paste-function / repeat-function etc.). >> But how can I expand a mathematical statement? >> >> >> thanks for any suggestions! >> ______________________________________________ >> R-help@r-project.org 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. >> > ______________________________________________ R-help@r-project.org 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.
