Re: [R] Reading and converting time data via read.table
>In fact, I learned most of them the hard way
>by trial and error and realized that it’s difficult to separate time and
>date using POSIXct and POSIXlt.
It is difficult to separate time from data in real life as well. The most
common problem is when your time zone switches between 'daylight
savings' ('summer') and 'standard' ('winter') each spring and fall.
You can attach your time to a fake date and arrange to only print the
time portion, but since you have a date, use it.
Bill Dunlap
TIBCO Software
wdunlap tibco.com
On Wed, Jun 8, 2016 at 10:40 PM, Ek Esawi wrote:
> Thank you Jeff and Don. As I stated on my original posting that I am
> relatively new to R. After a few weeks of searching and reading I have come
> to the same point that Don made which is base R doesn’t have a class for
> time only. I explored the chron and lubridate packages and even looked at
> Ecfun
> package; the latter is too long and I did not have time to experiment with
> it. I think the lubridate package might be useful for this; but again I did
> not want to get into many packages. So I tried chron using the times
> function that produced what I want. Indeed as Don said, I could not figure
> out how to use it in a read.table; so I had already decided to do what Don
> suggested which is read them as character then convert them one vector at a
> time to time class.
>
>
>
> What do I need this stuff for? Well, I published a paper 6 months ago where
> I had to deal with time data and needed to convert and manipulate time
> data. I did all that work in Excel and it took too long; so I want to learn
> R for future research and use the same data using R.
>
>
>
> I agree with Jeff’s comments. In fact, I learned most of them the hard way
> by trial and error and realized that it’s difficult to separate time and
> date using POSIXct and POSIXlt.
>
>
>
> Thanks againEK
>
> [[alternative HTML version deleted]]
>
> __
> R-help@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]]
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Re: [R] Reading and converting time data via read.table
Thank you Jeff and Don. As I stated on my original posting that I am relatively new to R. After a few weeks of searching and reading I have come to the same point that Don made which is base R doesn’t have a class for time only. I explored the chron and lubridate packages and even looked at Ecfun package; the latter is too long and I did not have time to experiment with it. I think the lubridate package might be useful for this; but again I did not want to get into many packages. So I tried chron using the times function that produced what I want. Indeed as Don said, I could not figure out how to use it in a read.table; so I had already decided to do what Don suggested which is read them as character then convert them one vector at a time to time class. What do I need this stuff for? Well, I published a paper 6 months ago where I had to deal with time data and needed to convert and manipulate time data. I did all that work in Excel and it took too long; so I want to learn R for future research and use the same data using R. I agree with Jeff’s comments. In fact, I learned most of them the hard way by trial and error and realized that it’s difficult to separate time and date using POSIXct and POSIXlt. Thanks againEK [[alternative HTML version deleted]] __ R-help@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.
Re: [R] Reading and converting time data via read.table
The canonical way to store times is as difftime vectors. However, there is no simple way to import e.g. HH:MM data directly into such vectors, so you need to embed such times into a longer string that includes a fixed date. After conversion to POSIXct you can subtract the fixed date to get the difftime values. It is also possible to let the conversion to POSIXct pick "today" by default, but you can sometimes get into trouble if you subtract out "today" on a different day, so I wouldn't recommend it. You also may encounter difficulty with daylight savings in this process... but that usually requires knowing a bit more about your data, and if you are already working with time only data you may not be able to fix such problems anyway. -- Sent from my phone. Please excuse my brevity. On June 8, 2016 10:20:38 AM PDT, "MacQueen, Don" wrote: >As far as I know, base R does not have a class for storing times that >are >not associated with a date, and recognizing that they are times. That >being the case, I don't think there is a way to convert them to some >sort >of time class while reading them into R using read.table(). I would >read >them into R as character strings, and then convert them (it would take >only a few extra lines of code). How you convert them depends on the >next >question, which is: > >What do you need to do with those times? > >For example, are T1 and T2 the times associated with two events that >both >occurred on the specified Date? If that is the case, I would probably >form >two POSIXct variables by combining the Date with T1 and the Date with >T2. >Or, do you just need to be able to sort your data by T1, or by T2? Or >do >you need to calculate the time differences (such as T2-T1) to get the >number of minutes between those two times? > >-Don > >-- >Don MacQueen > >Lawrence Livermore National Laboratory >7000 East Ave., L-627 >Livermore, CA 94550 >925-423-1062 > > > > > >On 6/5/16, 5:53 AM, "R-help on behalf of Ek Esawi" > wrote: > >>Hi All-- >> >> >> >>I am relatively new to R. I am reading a csv file via read.table >(MyFile). >>The data types in the file are date, string, integer, and time. I was >able >>to read all the data and manipulated correctly except time, e.g., >12:30. I >>used as.Date to convert date and string and integer were easily done. >I >>could not figure out how to convert the time data correctly. I tried >chron >>but w/o success and I read that POSIXlt and POSIXct work only for date >and >>time (e.g. 01/02/1999, 12:30:20). I did not try the lubridate package. >Is >>there a way to read time data without date attached to it like mine? >> >> >> >>I am grateful for any help and thanks in advance‹EKE >> >> >> >>Here is an example of my data when read into R via read.table >> >> >> >>AA Date Name T1 T2 >>N1 >> >>1 312171 7/1/1995 OF 13:37 1:43 >123 >> >> [[alternative HTML version deleted]] >> >>__ >>R-help@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. > >__ >R-help@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@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.
Re: [R] Reading and converting time data via read.table
As far as I know, base R does not have a class for storing times that are not associated with a date, and recognizing that they are times. That being the case, I don't think there is a way to convert them to some sort of time class while reading them into R using read.table(). I would read them into R as character strings, and then convert them (it would take only a few extra lines of code). How you convert them depends on the next question, which is: What do you need to do with those times? For example, are T1 and T2 the times associated with two events that both occurred on the specified Date? If that is the case, I would probably form two POSIXct variables by combining the Date with T1 and the Date with T2. Or, do you just need to be able to sort your data by T1, or by T2? Or do you need to calculate the time differences (such as T2-T1) to get the number of minutes between those two times? -Don -- Don MacQueen Lawrence Livermore National Laboratory 7000 East Ave., L-627 Livermore, CA 94550 925-423-1062 On 6/5/16, 5:53 AM, "R-help on behalf of Ek Esawi" wrote: >Hi All-- > > > >I am relatively new to R. I am reading a csv file via read.table (MyFile). >The data types in the file are date, string, integer, and time. I was able >to read all the data and manipulated correctly except time, e.g., 12:30. I >used as.Date to convert date and string and integer were easily done. I >could not figure out how to convert the time data correctly. I tried chron >but w/o success and I read that POSIXlt and POSIXct work only for date and >time (e.g. 01/02/1999, 12:30:20). I did not try the lubridate package. Is >there a way to read time data without date attached to it like mine? > > > >I am grateful for any help and thanks in advance‹EKE > > > >Here is an example of my data when read into R via read.table > > > >AA Date Name T1 T2 >N1 > >1 312171 7/1/1995 OF 13:37 1:43 123 > > [[alternative HTML version deleted]] > >__ >R-help@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. __ R-help@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.
Re: [R] Reading and converting time data via read.table
Hi
I am rather confused. If you have data in some external file, (csv, txt, tab
delimited), you can read it by corresponding read.* command to data.frame
object. I did not know about conversion to POSIX directly by reading an object
(it does not mean there is none).
After you read your data you can concatenate some variables to a character by
paste.
e.g.
tmp <- paste("7/1/1995", "13:37", sep=" ")
or
dat1 <- paste(Date, Time, sep=" ")
and you can use properly formated strptime to convert values to POSIX
strptime(tmp, format="%d/%m/%Y %H:%M")
Regards
Petr
> -Original Message-
> From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Ek Esawi
> Sent: Wednesday, June 8, 2016 12:26 AM
> To: r-help@r-project.org
> Subject: Re: [R] Reading and converting time data via read.table
>
> Thanks Petr!
>
>
>
> I am still unable to come up with a conversion formula/trick to convert my
> time data to POSIXlt which then can be used in read.table. Below are again a
> few lines from my file. Since as you see there are several columns of time
> data ONLY (no date), I am hoping that there is a way to convert the time
> columns to POSIXlt or chron in the read.table statement. I was able to use
> as.Date in the read.table to convert the dates.
>
>
> Thanks-EK
>
>
>
>O Date Name Time Inter Dura Prep Hht
> Pred
>
> 1 312171 7/1/1995 Old-1 13:37 1:43 4:42 13:16 162
> 13:19
>
> 2 358237 5/25/1993Old-2 12:22 1:31 4:16 12:03 160
> 12:13
>
> 3 339971 7/17/1994Old-3 15:54 1:23 4:36 15:43 160
> 15:51
>
> [[alternative HTML version deleted]]
>
> __
> R-help@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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Re: [R] Reading and converting time data via read.table
Thanks for the responses i received from David and Spencer. As for the package Ecfun, i looked at it briefly, but it's long and i am new to R; so this just adds to my confusion. David suggested the sub function which i will try and see what i get.i s As i said earlier i have no problems reading dates w/o time and i was able to produce a function that can be included in colClasses to reformat date correctly and convert them to class date. i even stumbled on a way to convert my time data to time class via the chron package. Here is what i did times(paste0(t1, ":00")) where t1 is the first element of the column named Time. The problem i have now is how to incorporate this function/command into the colClasses in read.table so that i don't have to convert every entry in each column, one at a time. Thank you for the help. EK [[alternative HTML version deleted]] __ R-help@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.
Re: [R] Reading and converting time data via read.table
Have you considered asNumericDF in the Ecfun package? This can
convert to a date-time column into POSIXct -- not POSIXlt -- using the
POSIX argument to identify the POSIX columns and format to provide the
"format" argument for as.POSIXct.
I suggest you try the R-Forge version: install.packages("Ecfun",
repos="http://R-Forge.R-project.org";). If I recall correctly, the
R-Forge version works the same as the CRAN version for POSIX but fixes a
subtle bug for Dates.
Hope this helps.
Spencer Graves
p.s. If anyone knows a better way to do this, I'm interested.
On 6/7/2016 5:26 PM, Ek Esawi wrote:
Thanks Petr!
I am still unable to come up with a conversion formula/trick to convert my
time data to POSIXlt which then can be used in read.table. Below are again
a few lines from my file. Since as you see there are several columns of
time data ONLY (no date), I am hoping that there is a way to convert the
time columns to POSIXlt or chron in the read.table statement. I was able to
use as.Date in the read.table to convert the dates.
Thanks-EK
O Date Name Time Inter Dura Prep Hht
Pred
1 312171 7/1/1995 Old-1 13:37 1:43 4:42 13:16 162
13:19
2 358237 5/25/1993Old-2 12:22 1:31 4:16 12:03 160
12:13
3 339971 7/17/1994Old-3 15:54 1:23 4:36 15:43 160
15:51
[[alternative HTML version deleted]]
__
R-help@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.
__
R-help@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.
Re: [R] Reading and converting time data via read.table
Thanks Petr! I am still unable to come up with a conversion formula/trick to convert my time data to POSIXlt which then can be used in read.table. Below are again a few lines from my file. Since as you see there are several columns of time data ONLY (no date), I am hoping that there is a way to convert the time columns to POSIXlt or chron in the read.table statement. I was able to use as.Date in the read.table to convert the dates. Thanks-EK O Date Name Time Inter Dura Prep Hht Pred 1 312171 7/1/1995 Old-1 13:37 1:43 4:42 13:16 162 13:19 2 358237 5/25/1993Old-2 12:22 1:31 4:16 12:03 160 12:13 3 339971 7/17/1994Old-3 15:54 1:23 4:36 15:43 160 15:51 [[alternative HTML version deleted]] __ R-help@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.
Re: [R] Reading and converting time data via read.table
Hi
> -Original Message-
> From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Ek Esawi
> Sent: Sunday, June 5, 2016 2:54 PM
> To: r-help@r-project.org
> Subject: [R] Reading and converting time data via read.table
>
> Hi All--
>
>
>
> I am relatively new to R. I am reading a csv file via read.table (MyFile).
> The data types in the file are date, string, integer, and time. I was able to
> read all the data and manipulated correctly except time, e.g., 12:30. I used
> as.Date to convert date and string and integer were easily done. I could not
> figure out how to convert the time data correctly. I tried chron but w/o
> success and I read that POSIXlt and POSIXct work only for date and time (e.g.
If you used strptime for converting your datae/time value you can tune it by
format to be able to read differently formated data.
> strptime("01/02/1999, 12:30:20", format="%d/%m/%Y, %H:%M:%S")
[1] "1999-02-01 12:30:20 CET"
> strptime("01/02/1999, 12:30", format="%d/%m/%Y, %H:%M")
[1] "1999-02-01 12:30:00 CET"
> strptime("01/02/1999, 12", format="%d/%m/%Y, %H")
[1] "1999-02-01 12:00:00 CET"
>
> str(strptime("01/02/1999, 12", format="%d/%m/%Y, %H"))
POSIXlt[1:1], format: "1999-02-01 12:00:00"
>
Regards
Petr
> 01/02/1999, 12:30:20). I did not try the lubridate package. Is there a way to
> read time data without date attached to it like mine?
>
>
>
> I am grateful for any help and thanks in advance—EKE
>
>
>
> Here is an example of my data when read into R via read.table
>
>
>
> AA Date Name T1 T2
> N1
>
> 1 312171 7/1/1995 OF 13:37 1:43 123
>
> [[alternative HTML version deleted]]
>
> __
> R-help@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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- a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně přijmout;
Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí nabídky ze strany příjemce
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- odesílatel tohoto emailu informuje, že není oprávněn uzavírat za společnost
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expres
Re: [R] Reading and converting time data via read.table
Thanks Jim! The problem is not date data. The problem is time. I figured out that I can use chron library and then use this expression times(paste0(t2, ":00")) because my time data are not h:m:s, only h;m. The problem I am trying to figure out is how to implement [times(paste0(t2, ":00"))] on colclasses so that the whole table is converted to correct time format which later can be manipulated Thanks again--EK. [[alternative HTML version deleted]] __ R-help@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.
Re: [R] Reading and converting time data via read.table
Hi EKE, Your problem may be that the date strings are being read as a factor. Try using stringsAsFactors=FALSE when you read the data in. Another way is to convert your dates to strings when passing to as.Date: as.Date(as.character(mydf$Date),"%m/%d/%Y") Jim On Sun, Jun 5, 2016 at 10:53 PM, Ek Esawi wrote: > Hi All-- > > > > I am relatively new to R. I am reading a csv file via read.table (MyFile). > The data types in the file are date, string, integer, and time. I was able > to read all the data and manipulated correctly except time, e.g., 12:30. I > used as.Date to convert date and string and integer were easily done. I > could not figure out how to convert the time data correctly. I tried chron > but w/o success and I read that POSIXlt and POSIXct work only for date and > time (e.g. 01/02/1999, 12:30:20). I did not try the lubridate package. Is > there a way to read time data without date attached to it like mine? > > > > I am grateful for any help and thanks in advance—EKE > > > > Here is an example of my data when read into R via read.table > > > > AA Date Name T1 T2 > N1 > > 1 312171 7/1/1995 OF 13:37 1:43 123 > > [[alternative HTML version deleted]] > > __ > R-help@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. __ R-help@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.
[R] Reading and converting time data via read.table
Hi All-- I am relatively new to R. I am reading a csv file via read.table (MyFile). The data types in the file are date, string, integer, and time. I was able to read all the data and manipulated correctly except time, e.g., 12:30. I used as.Date to convert date and string and integer were easily done. I could not figure out how to convert the time data correctly. I tried chron but w/o success and I read that POSIXlt and POSIXct work only for date and time (e.g. 01/02/1999, 12:30:20). I did not try the lubridate package. Is there a way to read time data without date attached to it like mine? I am grateful for any help and thanks in advance—EKE Here is an example of my data when read into R via read.table AA Date Name T1 T2 N1 1 312171 7/1/1995 OF 13:37 1:43 123 [[alternative HTML version deleted]] __ R-help@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.
