[R] Date Time in R
Shivi Bhatia
shivipmp82 at gmail.com
Tue Jul 26 18:54:37 CEST 2016
Hi Bill,
I have mentioned the transformation all on the email above.
Regards, Shivi
On Tue, Jul 26, 2016 at 10:19 PM, William Dunlap <wdunlap at tibco.com> wrote:
> Can you show us what transformations you tried when
> you saw the column called 'date' was a factor?
>
> Bill Dunlap
> TIBCO Software
> wdunlap tibco.com
>
> On Tue, Jul 26, 2016 at 9:33 AM, Shivi Bhatia <shivipmp82 at gmail.com>
> wrote:
>
>> Thanks Tom for the recommendation. This is now working.
>>
>> Apologies if this sounds like a juvenile but i am not very good with dates
>> in R. What i initially did when i saw date as factor and then tried
>> converting with lot many transformation that is where it went bad.
>>
>> But thanks to all this is really what i wanted.
>>
>> On Tue, Jul 26, 2016 at 9:58 PM, Tom Wright <tom at maladmin.com> wrote:
>>
>> > So this looks correct so far.
>> >
>> >
>> >
>> > # convert strings (or factors) to a date object
>> >
>> > a1$date <- as.Date(a1$date, “%m-%d-%y”)
>> >
>> >
>> >
>> > # Note the date object is now displayed in the format %Y-%m-%d by
>> default
>> >
>> > # so no need for the mdy() or ymd() function
>> >
>> >
>> >
>> > # extract the weekdays as number
>> >
>> > weekdays <- wday(a1$date)
>> >
>> >
>> >
>> > # note can’t have spaces in variable names
>> >
>> > week_names <- wday(a1$date, label=TRUE)
>> >
>> >
>> >
>> >
>> >
>> > *From:* Shivi Bhatia [mailto:shivipmp82 at gmail.com]
>> > *Sent:* July 26, 2016 12:16 PM
>> > *To:* Tom Wright <tom at maladmin.com>
>> > *Cc:* David L Carlson <dcarlson at tamu.edu>; r-help <r-help at r-project.org
>> >
>>
>> >
>> > *Subject:* Re: [R] Date Time in R
>> >
>> >
>> >
>> > Hello Tom,
>> >
>> >
>> >
>> > Please find the details: (i have changed name from eir to a1, rest all
>> is
>> > same)
>> >
>> >
>> >
>> > str(a1$date)
>> >
>> > Factor w/ 32 levels "05-30-16","05-31-16",..: 1 1 1
>> >
>> >
>> >
>> > head(a1$date)
>> >
>> > 05-30-16 05-30-16 05-30-16 05-30-16 05-30-16 05-30-16
>> >
>> > 32 Levels: 05-30-16 05-31-16 06-01-16 06-02-16 06-03-16 06-04-16
>> 06-05-16
>> > 06-06-16 06-07-16 06-08-16
>> >
>> >
>> >
>> > Thanks again!!!
>> >
>> >
>> >
>> > On Tue, Jul 26, 2016 at 9:38 PM, Tom Wright <tom at maladmin.com> wrote:
>> >
>> > Hi again Shiva,
>> > I think what we need to see is the output from:
>> >
>> > str(eid$date)
>> >
>> > and perhaps
>> > head(eid$date)
>> >
>> > If you can send this information before doing any processing on the date
>> > (i.e. before the as.Date() function) we may be able to help.
>> >
>> >
>> >
>> > -----Original Message-----
>> > From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Shivi
>> > Bhatia
>> > Sent: July 26, 2016 11:46 AM
>> > To: David L Carlson <dcarlson at tamu.edu>
>> > Cc: r-help <r-help at r-project.org>
>> > Subject: Re: [R] Date Time in R
>> >
>> > Hi David please see the code and some reproducible data:
>> > eir$date<- as.Date(eir$date,format = "%m-%d-%y") then i had used the
>> > lubridate library to help with the dates:
>> > install.packages("lubridate")
>> > library(lubridate)
>> > eir$date <- mdy(eir$date)
>> > weekdays <- wdy(eir$date)
>> > week names <- wdy(eir$date, label = TRUE)
>> >
>> > This the output from the file:
>> >
>> > structure(list(date = structure(c(NA_real_, NA_real_, NA_real_), class =
>> > "Date"),
>> >
>> > month = structure(c(2L, 2L, 2L), .Label = c("Jun","May"), class =
>> > "factor"),
>> >
>> > day = c(30L, 30L, 30L),
>> >
>> > weekday = structure(c(2L,2L, 2L), .Label = c("Fri", "Mon", "Sat", "Sun",
>> > "Thu", "Tue","Wed"), class = "factor"),
>> >
>> > survey_rating = c(3L, 2L, 3L), query_status = c("Yes", "Don't
>> know","No"),
>> >
>> > a = c("05-30-16", "05-30-16", "05-30-16")), .Names = c("date","month",
>> > "day", "weekday", "survey_rating"), row.names = c(NA, 3L), class =
>> > "data.frame")
>> >
>> > There are several other variables that i have removed which are not
>> > relevant
>> > in this context.
>> >
>> > On Tue, Jul 26, 2016 at 8:55 PM, David L Carlson <dcarlson at tamu.edu>
>> > wrote:
>> >
>> > > Show us the output, don’t just tell us what you are seeing. If the
>> > > dates are correct in the csv file, show us the structure of the data
>> > > frame you created with read.csv() and show the command(s) you used to
>> > > convert the character data to date format. The solution is likely to
>> > > be simple if you will cut/paste the R console and not just describe
>> what
>> > > is happening.
>> > >
>> > >
>> > >
>> > > David C
>> > >
>> > >
>> > >
>> >
>> > > *From:* Shivi Bhatia [mailto:shivipmp82 at gmail.com]
>> > > *Sent:* Tuesday, July 26, 2016 10:08 AM
>> > > *To:* David L Carlson
>> > >
>> > > *Subject:* Re: [R] Date Time in R
>> >
>> > >
>> > >
>> > >
>> > > Hi David,
>> > >
>> > > This gives the results accurately. The first line shows all the
>> > > variable names and the rest shows all values stored for each of the
>> > > variable. Here date is appearing as correct.
>> > >
>> > >
>> > >
>> > > Thanks, Shivi
>> > >
>> > >
>> > >
>> > > On Tue, Jul 26, 2016 at 7:39 PM, David L Carlson <dcarlson at tamu.edu>
>> > > wrote:
>> > >
>> > > 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.
>> > > >
>> > > >
>> > >
>> > > [[alternative HTML version deleted]]
>> > >
>> > > ______________________________________________
>> > > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> > > https://stat.ethz.ch/mailman/listinfo/r-help
>> >
>> > > <
>> https://urldefense.proofpoint.com/v2/url?u=https-3A__stat.ethz.ch_mai
>> > > lman_listinfo_r-2Dhelp&d=CwMFaQ&c=ODFT-G5SujMiGrKuoJJjVg&r=veMGHMCNZSh
>> > > ld-KX-bIj4jRE_tP9ojUvB_Lqp0ieSdk&m=s9RjgM0-LqObg32B_ODUoHMjaBJSYFn0ccx
>> > > orF0VRaQ&s=-2AvIVGKBvHIg4b3KBUCarOh98Mq95XbBM6rQR5o_Qw&e=>
>> > > PLEASE do read the posting guide
>> > > http://www.R-project.org/posting-guide.html
>> > > <
>> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.R-2Dproject.o
>> > > rg_posting-2Dguide.html&d=CwMFaQ&c=ODFT-G5SujMiGrKuoJJjVg&r=veMGHMCNZS
>> > > hld-KX-bIj4jRE_tP9ojUvB_Lqp0ieSdk&m=s9RjgM0-LqObg32B_ODUoHMjaBJSYFn0cc
>> > > xorF0VRaQ&s=Ldb33UyU9KMUXEsxxzwItyCFjZInukICij2jo66xaKg&e=>
>> >
>> > > and provide commented, minimal, self-contained, reproducible code.
>> > >
>> > >
>> > >
>> >
>> > [[alternative HTML version deleted]]
>> >
>> > ______________________________________________
>> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> > 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 at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> 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.
>>
>
>
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