Hi together, thank you so much for your help! The problem was indeed the strptime-function. Replacing that with as.Date solves the problem, both in the example I provided and in my actual data set.
I think this is a lesson for me to not use types I'm not really familiar with (POSIXlt in this case). Thanks again! Christoph On Mon, Apr 25, 2011 at 10:07 PM, Hadley Wickham <had...@rice.edu> wrote: > > > If you need plyr for other tasks you ought to use a different > > class for your date data (or wait until plyr can deal with > > POSIXlt objects). > > How do you get POSIXlt objects into a data frame? > > > df <- data.frame(x = as.POSIXlt(as.Date(c("2008-01-01")))) > > str(df) > 'data.frame': 1 obs. of 1 variable: > $ x: POSIXct, format: "2008-01-01" > > > df <- data.frame(x = I(as.POSIXlt(as.Date(c("2008-01-01"))))) > > str(df) > 'data.frame': 1 obs. of 1 variable: > $ x: AsIs, format: "0" > > Hadley > > -- > Assistant Professor / Dobelman Family Junior Chair > Department of Statistics / Rice University > http://had.co.nz/ -- -------------------------------------------------------------------------------------------------------------------------------------------------------------------- Christoph Jäckel (Dipl.-Kfm.) -------------------------------------------------------------------------------------------------------------------------------------------------------------------- Research Assistant Chair for Financial Management and Capital Markets | Lehrstuhl für Finanzmanagement und Kapitalmärkte TUM School of Management | Technische Universität München Arcisstr. 21 | D-80333 München | Germany Mailto: christoph.jaec...@wi.tum.de | Web: www.fm.wi.tum.de Phone: +49 89 289 25482 | Fax: +49 89 289 25488 Head of Chair: Univ.-Prof. Dr. Christoph Kaserer ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- E-Mail Disclaimer Der Inhalt dieser E-Mail ist vertraulich und ausschliesslich fuer den bezeichneten Adressaten bestimmt. Wenn Sie nicht der vorgesehene Adressat dieser E-Mail oder dessen Vertreter sein sollten, so beachten Sie bitte, dass jede Form der Kenntnisnahme, Veroeffentlichung, Vervielfaeltigung oder Weitergabe des Inhalts dieser E-Mail unzulaessig ist. Wir bitten Sie, sich in diesem Fall mit dem Absender der E-Mail in Verbindung zu setzen. The information contained in this email is confidential....{{dropped:11}} ______________________________________________ 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.