Hi Bill, Please keep the R list copied. I don't think you've given enough information to pin down your problem. This works:
dat <- read.table(textConnection("dates returns 2000-1-4 -0.038344718 2000-1-5 0.001922225 2000-1-6 0.000955702 2000-1-7 0.027090384 2000-1-10 0.011189966 2000-1-11 -0.013062569 2000-1-12 -0.004386331 2000-1-13 0.012169663 2000-1-14 0.010671321 2000-1-18 -0.006832065 2000-1-19 0.000522287 2000-1-20 -0.007095268 2000-1-21 -0.002912346"), header=TRUE) closeAllConnections() attach(dat) i=1 while(i<14){ if(weekdays(as.Date(dates[i])) == "Monday"){ print ("yes") } else { print("no") } i=1+i } detach(dat) Best, Ista On Tue, Nov 30, 2010 at 11:22 PM, Bill Yang <gy631...@hotmail.com> wrote: > Hi Ista, > I appreciate for your reply. > I am running into another problem now, the following is my date (example) > 2000-1-4 -0.038344718 > 2000-1-5 0.001922225 > 2000-1-6 0.000955702 > 2000-1-7 0.027090384 > 2000-1-10 0.011189966 > 2000-1-11 -0.013062569 > 2000-1-12 -0.004386331 > 2000-1-13 0.012169663 > 2000-1-14 0.010671321 > 2000-1-18 -0.006832065 > 2000-1-19 0.000522287 > 2000-1-20 -0.007095268 > 2000-1-21 -0.002912346 > Let'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 codes > i=1 > while(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 > > >> From: iz...@psych.rochester.edu >> Date: Tue, 30 Nov 2010 21:59:50 -0500 >> Subject: Re: [R] Welcome to the "R-help" mailing list >> To: gy631...@hotmail.com >> CC: r-help@r-project.org >> >> Hi Bill, >> You might be working too hard. Consider: >> > weekdays(as.Date('2010-11-30')) == "Monday" >> [1] FALSE >> > weekdays(as.Date('2010-11-29')) == "Monday" >> [1] TRUE >> > >> >> HTH, >> Ista >> >> On Tue, Nov 30, 2010 at 9:40 PM, Bill Yang <gy631...@hotmail.com> wrote: >> > >> > Hi there, >> > I am having problem of matching string. what i want is when i type a >> > date such as 2010-11-30, the function will return the day (monday, tuesday, >> > wednesday, thursday, friday or staturday). then i want another function >> > will >> > return true if the return of the day is monday, return false if the return >> > of the day is not monday. >> > I already find the weekdays(as.Date('2010-11-30')) function which will >> > tell me exactly what day its gonna be. however, i am having problem of >> > return True or False whether or not the return day has matched. >> > please help me out. I appreciate. >> > Bill >> > P.S the following is the partial >> > codes.if(match(weekdays(as.Date('2010-11-30'), "Monday")==1){print("yes")} >> > >> > >> > >> > r-help@r-project.org >> >> 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. >> > >> >> >> >> -- >> Ista Zahn >> Graduate student >> University of Rochester >> Department of Clinical and Social Psychology >> http://yourpsyche.org > -- Ista Zahn Graduate student University of Rochester Department of Clinical and Social Psychology http://yourpsyche.org ______________________________________________ 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.