A fairly simple way is to generate one series with all the Tuesdays, then another with all the Thursdays, combine and sort.
> sort( c( seq.Date( as.Date('2010-6-29'), by='week', length.out=10), + seq.Date( as.Date('2010-7-1'), by='week', length.out=10) ) + ) [1] "2010-06-29" "2010-07-01" "2010-07-06" "2010-07-08" "2010-07-13" [6] "2010-07-15" "2010-07-20" "2010-07-22" "2010-07-27" "2010-07-29" [11] "2010-08-03" "2010-08-05" "2010-08-10" "2010-08-12" "2010-08-17" [16] "2010-08-19" "2010-08-24" "2010-08-26" "2010-08-31" "2010-09-02" > -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare greg.s...@imail.org 801.408.8111 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > project.org] On Behalf Of Simon Kiss > Sent: Tuesday, June 29, 2010 4:22 AM > To: r-help@r-project.org > Subject: [R] generate irregular series of dates > > Dear colleagues, particularly academic ones, > So I'm creating a Microsoft Word template for myself so that every > time I teach a new course, I don't have to enter in the dates manually > for each class session. > I'd like to use an R script that can generate an irregular series of > dates starting from one date (semester begin) to another (semester > end) using an irregular interval in between (Tuesdays and Thursdays, > for example). > I know that a regular series of dates is no problem, but what about an > irregular series? > Yours, > Simon Kisss > ********************************* > Simon J. Kiss, PhD > SSHRC and DAAD Post-Doctoral Fellow > John F. Kennedy Institute of North America Studies > Free University of Berlin > Lansstraße 7-9 > 14195 Berlin, Germany > Cell: +49 (0)1525-300-2812, > Web: http://www.jfki.fu-berlin.de/index.html > > ______________________________________________ > 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. ______________________________________________ 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.