Hi thereI appreciate for your reply.I am running into another problem now, the following is my date (example)2000-1-4 -0.0383447182000-1-5 0.0019222252000-1-6 0.0009557022000-1-7 0.0270903842000-1-10 0.0111899662000-1-11 -0.0130625692000-1-12 -0.0043863312000-1-13 0.0121696632000-1-14 0.0106713212000-1-18 -0.0068320652000-1-19 0.0005222872000-1-20 -0.0070952682000-1-21 -0.002912346Let's focus on the dates, by using weekdays(as.Date('2010-11-30')) == "Monday", im supposed to find the monday return (2nd column)i create an array which includes the dates, let's call it dates. then when i plug in the dates into the following codesi=1while(i<14){if(weekdays(as.Date(dates[i])) == "Monday"){pirnt ("yes")}else {print("no")}i=1+i}the programe does not run properly.......cuz im expecting to see "yes" been returned (there is not any "no" returned, all of them are "yes"......). i guess dates[i] returns "2010-1-1", but the as.Date requires '2010-1-1! '.. please help me out. I appreciate.Bill
> Subject: Welcome to the "R-help" mailing list > From: r-help-requ...@r-project.org > To: gy631...@hotmail.com > Date: Wed, 1 Dec 2010 03:34:01 +0100 > > Welcome to the R-help@r-project.org mailing list! > > To post to this list, send your email to: > > r-help@r-project.org > > General information about the mailing list is at: > > https://stat.ethz.ch/mailman/listinfo/r-help > > If you ever want to unsubscribe or change your options (eg, switch to > or from digest mode, change your password, etc.), visit your > subscription page at: > > https://stat.ethz.ch/mailman/options/r-help/gy631223%40hotmail.com > > You can also make such adjustments via email by sending a message to: > > r-help-requ...@r-project.org > > with the word `help' in the subject or body (don't include the > quotes), and you will get back a message with instructions. > > You must know your password to change your options (including changing > the password, itself) or to unsubscribe. It is: > > 8711208752 > > Normally, Mailman will remind you of your r-project.org mailing list > passwords once every month, although you can disable this if you > prefer. This reminder will also include instructions on how to > unsubscribe or change your account options. There is also a button on > your options page that will email your current password to you. [[alternative HTML version deleted]] ______________________________________________ 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.