Thanks for that Ben, I appreciate it a lot. I have another question if you don't mind taking the time to answer it. I want to create a subset from dataset called "datafile5" with only the variables "Date," "PM2.5 mean concentration," "SITE_LONGITUDE," and "SITE_LATITUDE," dating only in September 2009.
Do you know how I can do this? -- View this message in context: http://r.789695.n4.nabble.com/Categorizing-by-month-tp4705173p4705208.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
