Hi Tim Chatterton <tim.chatter...@uwe.ac.uk> napsal dne 02.07.2009 13:19:46:
> > Actually it is a character and you need to convert it to numbers by as.numeric > > This is the bit I have problems with - I can easily get it out as characters > but I cannot work out how to use as.numeric (and had actually given up as it > seemed to only want to work on numeric fields not character fields). > > Any idea how I do the character to numeric conversion? > Thanks, > Tim. What is the problem with > format(strptime("20/2/06 11:16:16.683", "%d/%m/%y %H:%M:%OS"), "%m") [1] "02" > as.numeric(format(strptime("20/2/06 11:16:16.683", "%d/%m/%y %H:%M:%OS"), "%m")) [1] 2 Regards Petr > > > Petr PIKAL wrote: > Hi > > r-help-boun...@r-project.org napsal dne 02.07.2009 12:40:05: > > > I have a data frame (hf) that is all set up and the dates are working > fine - however I need to extract the months and hours (2 separate > columns) as numbers - however they are coming out as characters. > > I have tried both the following: > > hf50$hour= hf50$date > hf50$hour=format(hf50["hour"],"%H") > > and > > hf$month <- as.POSIXct(strptime(hf$date, format = "%m")) > > > If hf$date is in POSIX format then > > format(hf$date,"%m") > > shall give you month as a number 01-12. Actually it is a character and you > need to convert it to numbers by as.numeric. > > If it is in different format then depending on how it is actually > formatted you can use strptime to transform it to POSIX class and then to > use format to extract only days or months from it. > > Regards > Petr > > > > > but they are still coming out as characters. > > Any ideas please? > Thanks, > Tim. > > ______________________________________________ > 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. > > > > > This incoming email to UWE has been independently scanned for viruses by > McAfee anti-virus software and none were detected > > > -- > > > __________________________________________ > > Dr Tim Chatterton > Senior Research Fellow > Air Quality Management Resource Centre > Faculty of Environment and Technology > University of the West of England > Frenchay Campus > Bristol > BS16 1QY > > Tel: 0117 328 2929 > Fax: 0117 328 3360 > Email: tim.chatter...@uwe.ac.uk ______________________________________________ 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.