Why not just round the floating point numbers to ensure they're equal with zapsmall, round or signif?
Hadley On Fri, Jul 4, 2014 at 4:04 AM, Sebastian Schubert <schubert....@gmail.com> wrote: > Hi, > > I would like to ask for best practice advice on the design of data > structure and the connected analysis techniques. > > In my particular case, I have measurements of several variables at > several, sometimes equal, heights. Following the tidy data approach of > Hadley Wickham, I want to put all data in one data frame. In principle, > the height variable is something like a category. For example, I want to > average over time for every height. Using dplyr this works very well > when my height variable is a factor. However, if it is not a factor the > grouping sometimes will not work probably due to numerical issues: > > http://stackoverflow.com/questions/24555010/dplyr-and-group-by-factor-vs-no-factor > https://github.com/hadley/dplyr/issues/482 > > Even if the behaviour described in the links above is a bug, on can > easily create other numerical issues in R: >> (0.1+0.2) == 0.3 > [1] FALSE > > Thus, it seems one should avoid grouping by float values and, in my > case, use factors. However, from time to time, I need the numerical > character of the heights: compare heights, find the maximum height, etc. > Here, the ordered factor approach might help. However, I have to combine > (via rbind or merge) different data sets quite often so keeping the > order of the different ordered factor heights also seem to be difficult. > > Is there any general approach which reduces the work or do I have to > switch between approaches as needed? > > Thanks a lot for any input, > Sebastian > > ______________________________________________ > 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. -- http://had.co.nz/ ______________________________________________ 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.
