Hi list, I have some questions regarding 1) conversion of date + time characters to chron 2) formatting chron object printing
Regarding (1), Gabor's Rnews 2004 4/1 article has been indispensible, but I often work with files where dates and times are contained in a single field. In this case, I would like to control input/output of chron objects when each observation of date and time is stored as a single string. So here are some procedures that I've tried: ## define character vector > x <- c("07/01/2001 12:00:00","07/17/2001 15:00:00") ## method 1 > library(chron) > chron(substring(x,1,10),substring(x,12)) [1] (07/01/01 12:00:00) (07/17/01 15:00:00) ## method 2 (recently inspired by Gabor's post) > do.call(c,strapply(x,"(.*) (.*)",chron,backref=-2)) [1] (07/01/01 12:00:00) (07/17/01 15:00:00) ## method 3 > (chronObj <- as.chron(strptime(x,"%m/%d/%Y %T"))) [1] (07/01/01 12:00:00) (07/17/01 15:00:00) Could there be any gotchas with the third method (as.chron(strptime(...)))? The 'tz' attribute for POSIXlt objects are ignored, but I am not sure if there are any implications of the '$isdst' field are for conversions. I do like this alternative for the conciseness-flexibility tradeoff; in my experience, I have not had any problems - but wanted to inquire if at some point the '$isdst' field (or possibly something else) could give me trouble. Regarding the printing of chron objects, this behavior is peculiar to me: > format(chronObj,format=c("m/d","h:m")) [1] "(0701 1200)" "(0717 1500)" The special characters ("/",":") are not printed - I've tried changing the attribute of the chron object, looked at the format.chron() method (getS3method("format","chron")), etc. and am still confused; the chron() documentation says its specification should be similar the input format. Could I have missed something? Thanks! ST ______________________________________________ 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.