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.pikal@precheza.cz> wrote:

> Hi
>
> > -----Original Message-----
> > From: r-help-bounces@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]]
> >
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>

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