What does this produce?
> readLines("YourCSVfilename.csv", n=5)
If the data are in Excel, the date format used in .csv files is not always in
the same as the format used when viewing dates in the spreadsheet.
-------------------------------------
David L Carlson
Department of Anthropology
Texas A&M University
College Station, TX 77840-4352
-----Original Message-----
From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Shivi Bhatia
Sent: Tuesday, July 26, 2016 7:42 AM
To: Marc Schwartz
Cc: R-help
Subject: Re: [R] Date Time in R
Thanks Marc for the help. this really helps.
I think there is some issue with the data saved in csv format for this
variable as when i checked:
str(eir$date)- this results in :-
Date[1:5327], format: NA NA NA NA NA.
Thanks again.
On Tue, Jul 26, 2016 at 5:58 PM, Marc Schwartz <marc_schwartz at me.com>
wrote:
> Hi,
>
> That eir$date might be a factor is irrelevant. There is an as.Date()
> method for factors, which does the factor to character coercion internally
> and then calls as.Date.character() on the result.
>
> Using the example data below:
>
> eir <- data.frame(date = c("05-30-16", "05-30-16",
"05-30-16",
> "05-30-16", "05-30-16",
"05-30-16"))
>
> > str(eir)
> 'data.frame': 6 obs. of 1 variable:
> $ date: Factor w/ 1 level "05-30-16": 1 1 1 1 1 1
>
> > eir
> date
> 1 05-30-16
> 2 05-30-16
> 3 05-30-16
> 4 05-30-16
> 5 05-30-16
> 6 05-30-16
>
> eir$date <- as.Date(eir$date, format = "%m-%d-%y")
>
> > str(eir)
> 'data.frame': 6 obs. of 1 variable:
> $ date: Date, format: "2016-05-30" ...
>
> > eir
> date
> 1 2016-05-30
> 2 2016-05-30
> 3 2016-05-30
> 4 2016-05-30
> 5 2016-05-30
> 6 2016-05-30
>
> eir$days <- weekdays(eir$date)
>
> > str(eir)
> 'data.frame': 6 obs. of 2 variables:
> $ date: Date, format: "2016-05-30" ...
> $ days: chr "Monday" "Monday" "Monday"
"Monday" ...
>
> > eir
> date days
> 1 2016-05-30 Monday
> 2 2016-05-30 Monday
> 3 2016-05-30 Monday
> 4 2016-05-30 Monday
> 5 2016-05-30 Monday
> 6 2016-05-30 Monday
>
>
> I would check to be sure that you do not have any typos in your code.
>
> Regards,
>
> Marc Schwartz
>
>
> > On Jul 26, 2016, at 6:58 AM, Shivi Bhatia <shivipmp82 at
gmail.com> wrote:
> >
> > Hello Again,
> >
> > While i tried your solution as you suggested above it seems to be
> working.
> > Here is the output
> > temp<- dput(head(eir$date))
> > c("05-30-16", "05-30-16", "05-30-16",
"05-30-16", "05-30-16", "05-30-16")
> > however it still shows class(eir$date) as character and hence i cannot
> find
> > weekdays from this variable.
> >
> > Sorry but i still dont understand in totality how R reads dates even
> though
> > have tried enough.
> >
> > Regards, Shivi
> >
> >
> > On Tue, Jul 26, 2016 at 5:12 PM, Shivi Bhatia <shivipmp82 at
gmail.com>
> wrote:
> >
> >> Thanks Duncan for the quick response. I will check again as you
> suggested.
> >> If that doesn't work i will share a reproducible example.
> >>
> >> Thanks again!!!!
> >>
> >> On Tue, Jul 26, 2016 at 4:43 PM, Duncan Murdoch <
> murdoch.duncan at gmail.com>
> >> wrote:
> >>
> >>> On 26/07/2016 7:05 AM, Shivi Bhatia wrote:
> >>>
> >>>> Hi Team,
> >>>>
> >>>> This scenario may have come across a number of times
however i checked
> >>>> nabble & SO and couldn't find a solution hence
request assistance.
> >>>>
> >>>> I have a date variable in my data-set eir. The class of
this var was
> >>>> character while i had read the file in r studio. Example
of date -
> >>>> 05-30-16
> >>>>
> >>>> To change this i have used eir$date<- as.Date(eir$date,
"%m-%d-%y").
> This
> >>>> converts it to a date variable. However when i check few
obs
> >>>> with head(eir$date) all the results are <NA>.
> >>>>
> >>>
> >>> I think you don't have character data like that, because I
see
> >>>
> >>>> as.Date("05-30-16", "%m-%d-%y")
> >>> [1] "2016-05-30"
> >>>
> >>> I'd guess eir$date is really a factor, because character
data is
> >>> frequently changed to factor automatically. If that's the
case, this
> >>> should work for the conversion:
> >>>
> >>> as.Date(as.character(eir$date), "%m-%d-%y")
> >>>
> >>> If that doesn't work, you'll need to post something
reproducible.
> >>>
> >>> Duncan Murdoch
> >>>
> >>> I also need to create weekdays from this date variable but
until i get
> >>>> this
> >>>> resolved i cant find a weekday. For weekday i have used:
> >>>> eir$week<- (eir$date)
> >>>> eir$week<- weekdays(as.Date(eir$week))
> >>>> class(eir$week)
> >>>> eir$week<- as.factor(eir$week)
> >>>> head(eir$week)
> >>>>
> >>>> Head of this eir$week results again as expected in
<NA> but shows
> Levels:
> >>>> Friday Monday Saturday Sunday Thursday Tuesday Wednesday
> >>>>
> >>>> Not sure what i should do here. Kindly suggest.
>
>
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