Thank you all for taking your time and looking at this problem. Yes, date handling is a problem with many languages. I have resolved the rbind not being able to handle different data formats in a column for this specific problem by making the data format a character and later convert back to numeric.
Thank you again On Mon, Nov 11, 2013 at 3:06 AM, PIKAL Petr <petr.pi...@precheza.cz> wrote: > Hi > > > -----Original Message----- > > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > > project.org] On Behalf Of Alemu Tadesse > > Sent: Friday, November 08, 2013 8:41 PM > > To: r-help@r-project.org > > Subject: [R] Date handling in R is hard to understand > > > > Dear All, > > > > I usually work with time series data. The data may come in AM/PM date > > format or on 24 hour time basis. R can not recognize the two > > differences automatically - at least for me. I have to specifically > > tell R in which time format the data is. It seems that Pandas knows how > > to handle date without being told the format. The problem arises when I > > try to shift time by a certain time. Say adding 3600 to shift it > > forward, that case I have to use something like: > > Measured_data$Date <- as.POSIXct(as.character(Measured_data$Date), > > tz="",format = "%m/%d/%Y %I:%M %p")+3600 or Measured_data$Date <- > > as.POSIXct(as.character(Measured_data$Date), > > tz="",format = "%m/%d/%Y %H:%M")+3600 depending on the format. The > > date also attaches MDT or MST and so on. When merging two data frames > > with dates of different format that may create a problem (I think). > > When I get data from excel it could be in any/random format and I > > needed to customize the date to use in R in one of the above formats. > > Any TIPS - for automatic processing with no need to specifically tell > > the data format ? > > > > Another problem I saw was that when using r bind to bind data frames, > > if one column of one of the data frames is a character data (say for > > example none - coming from mysql) format R doesn't know how to > > concatenate numeric column from the other data frame to it. I needed to > > rbind/cbind can use data.frame method which add any column specific > format. However with "normal" method, it results in matrix which has to > have common type of data in all columns (actually matrix is only vector > with dimensions). > > > str(cbind(airquality, 1:153)) > 'data.frame': 153 obs. of 7 variables: > $ ozone : int 41 36 12 18 NA 28 23 19 8 NA ... > $ solar.r: int 190 118 149 313 NA NA 299 99 19 194 ... > $ wind : num 7.4 8 12.6 11.5 14.3 14.9 8.6 13.8 20.1 8.6 ... > $ temp : int 67 72 74 62 56 66 65 59 61 69 ... > $ month : int 5 5 5 5 5 5 5 5 5 5 ... > $ day : int 1 2 3 4 5 6 7 8 9 10 ... > $ 1:153 : int 1 2 3 4 5 6 7 8 9 10 ... > > Regards > Petr > > > > change the numeric to character and later after binding takes place I > > had to re-convert it to numeric. But, this causes problem in an > > automated environment. Any suggestion ? > > > > Thanks > > Mihretu > > > > [[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. > [[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.
