Greg Snow <greg.s...@imail.org> [Sat, Jun 19, 2010 at 12:44:48AM CEST]: > There are a lot of other reasons to install the fortunes package that just > the one fortune, there is much wisdom, some wit, (and then there are mine) > throughout the package. >
Sorry, but I am subscribing to r-help already. I could not possibly handle more wisdom and wit than this. > There could be other ways to accomplish your goals, if you let us know more > about what you are trying to do, we may be able to help you find a better way > (that does not mean that you cannot still use eval and parse, but you may > learn something, and/or avoid future pitfalls). Ok, I want to demonstrate for educational purposes how to construct a set of rules to validate a set of clinical data, and to make it issue and export appropriate query messages. A rule would be a data structure containing the ID of the rule, the rule in human readable language, an expression evaluating variables within the environment of the appropriate data frame (and resolving to a logical vector), possibly the data frame itself, and the query message (possibly as an sprintf expression). The data structure may be an S4 object or a list. In our current workflow, we manage the validation rules using a spreadsheet, and import them into a competitor's analysis software. I could pass function(df) with(df, (vsstresn < 30 | vsstresn > 130) & vstestcd == "HR") as an argument, but "function(df) with(df," is sort of redundant, as I expect it to be in every expression, plus it doesn't add much clarity for the people writing and reading these conditions. [...] > Personally I have never regretted trying not to underestimate my own future > stupidity. > -- Greg Snow (explaining why eval(parse(...)) is often suboptimal, > answering > a question triggered by the infamous fortune(106)) > R-help (January 2007) Don't get me started about my current stupidity. -- Johannes Hüsing There is something fascinating about science. One gets such wholesale returns of conjecture mailto:johan...@huesing.name from such a trifling investment of fact. http://derwisch.wikidot.com (Mark Twain, "Life on the Mississippi") ______________________________________________ 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.