G'day Bill, On Wed, 27 Oct 2010 10:34:27 +1100 <bill.venab...@csiro.au> wrote:
[...] > It is no surprise that this does not work when working in the real > domain, except "by fluke" with something like > > > -4^(1/3) > [1] -1.587401 > > > > where the precedence of the operators is not what you might expect. > Now that could be considered a bug, since apparently > > > -4^(1/2) > [1] -2 > > which comes as rather a surprise! [...] Mate, you must have been using Excel (or bc) too much recently if this takes you by surprise. :) This is exactly the behaviour that I would expect as I was always taught that exponentiation was the operator with the highest priority. The discussion at http://en.wikipedia.org/wiki/Order_of_operations points out that "there exist differing conventions concerning the unary operator -" but gives only Excel and bc as examples of programs/languages who give the unary operator the higher precedence. Moreover, http://www.burns-stat.com/pages/Tutor/spreadsheet_addiction.html points out that in Excel "the precedence of unary minus is different than many other languages (including VBA which is often used with Excel)". Cheers, Berwin ______________________________________________ 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.