Hi Markus, On 2/9/10 4:12 PM, Markus Weisner wrote:
Thanks so much for your help. I am realizing that I may be over-complicating things for myself. I have learned a ton about creating methods, but I feel like I am trying to reinvent the data.frame class. Basically, I am trying to create a data.frame type object where I can enforce the header names and column data types. I am trying to force the user to setup the following fields:- event_number (character) - agency (factor) - unit_num (factor) - alarm (POSIXct) - priority (factor) A user might use the following code: event_number = c(1:5) agency = c("CFD", rep("ACFR", 3), "CFD") unit_num = c("E1", "T10", "E3", "E2", "BC1") temp = c("00:52:35", "06:58:18", "13:42:18", "20:59:45", "21:19:00") alarm = as.POSIXct(strptime(temp, format="%H:%M:%S")) priority = c("A", "E", "A", "C", "C") data = data.frame(event_number=event_number, agency=agency, unit_number=unit_num, alarm=alarm, priority=priority) I have all sorts of functions that I am trying to incorporate into a package for analyzing fire department data, but keep having problems with small deviations in data format causing errors. In this example, the following might cause issues in my functions: - "event_number" should be of type character - "agency", "unit_number", and "priority", should be of type factor - "unit_number" should actually have name "unit_num"
Perhaps you could simply provide a helper function for creating plain data.frames that does this validity checking? You could also provide a validate function that takes a data.frame and either says "OK" or describes the ways in which the input does not conform.
I think the benefits you would get out of a complete S4 wrapping of data.frame do not outweigh the complexity introduced.
+ seth -- Seth Falcon | @sfalcon | http://userprimary.net/user ______________________________________________ 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.
