You want %Y, not %y.
You might also want to look at the zoo package:
library(zoo)
z <- read.zoo("Date1.txt", header = TRUE, sep = ",", format = "%m/%d/%Y")
or using chron:
library(zoo)
library(chron)
z <- read.zoo("Date1.txt", header = TRUE, sep = ",", FUN = as.chron)
There are three vignettes that come with zoo that have more info.
On Sat, Jul 11, 2009 at 1:10 PM, Mark Knecht <markkne...@gmail.com> wrote:
> Hi all,
> I'm having a little bit of trouble with some date conversions and
> am hoping someone can help me out. Thanks in advance.
>
> OK, I have two sources of data that provide date info in a csv file
> differently. I've attached a small zipped file with two text files
> that illustrate both. (Is it ok to send attachments to this list? Not
> sure. It's very small.) I need to be able to check dates in one file
> against ranges in the other. For comparison I sort of like the format
> where Jan 3, 2004 would be 1040103 (104 years since 1900, etc.) and
> since that file seems to convert into R dates I don't think I need too
> much help there. However the other file is using a pretty standard
> M/D/Y format and I cannot seem to get it converted into R dates. No
> complaints from R but I have two issues with the results:
>
> 1) The year 2004 is showing up as 2020 after conversion. That's just wrong.
> 2) Sometimes I get NAs. That I don't understand.
>
> Can anyone see what I'm doing wrong here? As I say, I think I'd
> like to convert 01/03/2004 into 1040103 as this numeric format seems
> very good for doing comparisons.
>
> The code:
>
> MyDate1 = read.csv("C:\\Date1.txt",header=TRUE)
> MyDate2 = read.csv("C:\\Date2.txt",header=TRUE)
>
> MyDate1
> Date1 = MyDate1$Date
> class(Date1)
> mode(Date1)
> Date1
> Date1 = as.Date(Date1, "%m/%d/%y")
> class(Date1)
> mode(Date1)
> Date1
>
>
> MyDate2
> Date2 = MyDate2$EnDate
> class(Date2)
> mode(Date2)
> Date2
> Date2 = strptime(Date2 + 19e6L, "%Y%m%d")
> class(Date2)
> mode(Date2)
> Date2
> Date2 = as.Date(Date2)
> class(Date2)
> mode(Date2)
> Date2
>
> Results follow.
>
> Thanks,
> Mark
>
>
> > MyDate1 = read.csv("C:\\Date1.txt",header=TRUE)
> > MyDate2 = read.csv("C:\\Date2.txt",header=TRUE)
> >
> > MyDate1
> Date Time
> 1 01/02/2003 1315
> 2 01/03/2003 1315
> 3 01/06/2003 1315
> 4 01/07/2003 1315
> 5 01/08/2003 1315
> 6 01/09/2003 1315
> 7 01/10/2003 1315
> 8 01/13/2003 1315
> 9 01/14/2003 1315
> 10 01/15/2003 1315
> 11 01/16/2003 1315
> 12 01/17/2003 1315
> > Date1 = MyDate1$Date
> > class(Date1)
> [1] "factor"
> > mode(Date1)
> [1] "numeric"
> > Date1
> [1] 01/02/2003 01/03/2003 01/06/2003 01/07/2003 01/08/2003 01/09/2003
> 01/10/2003 01/13/2003 01/14/2003 01/15/2003 01/16/2003 01/17/2003
> Levels: 01/02/2003 01/03/2003 01/06/2003 01/07/2003 01/08/2003
> 01/09/2003 01/10/2003 01/13/2003 01/14/2003 01/15/2003 01/16/2003
> 01/17/2003
> > Date1 = as.Date(Date1, "%m/%d/%y")
> > class(Date1)
> [1] "Date"
> > mode(Date1)
> [1] "numeric"
> > Date1
> [1] "2020-01-02" "2020-01-03" "2020-01-06" "2020-01-07" "2020-01-08"
> "2020-01-09" "2020-01-10" "2020-01-13" "2020-01-14" "2020-01-15"
> "2020-01-16"
> [12] "2020-01-17"
> >
> >
> > MyDate2
> Trade PosType EnDate EnTime ExDate ExTime
> 1 1 -1 1040127 919 1040127 932
> 2 2 1 1040127 1155 1040127 1208
> 3 3 -1 1040127 1300 1040127 1313
> 4 4 -1 1040128 958 1040128 1313
> 5 5 -1 1040129 1024 1040129 1129
> 6 6 1 1040129 1234 1040129 1313
> 7 7 1 1040202 906 1040202 1129
> 8 8 -1 1040202 1129 1040202 1313
> > Date2 = MyDate2$EnDate
> > class(Date2)
> [1] "numeric"
> > mode(Date2)
> [1] "numeric"
> > Date2
> [1] 1040127 1040127 1040127 1040128 1040129 1040129 1040202 1040202
> > Date2 = strptime(Date2 + 19e6L, "%Y%m%d")
> > class(Date2)
> [1] "POSIXt" "POSIXlt"
> > mode(Date2)
> [1] "list"
> > Date2
> [1] "2004-01-27 GMT" "2004-01-27 GMT" "2004-01-27 GMT" "2004-01-28
> GMT" "2004-01-29 GMT" "2004-01-29 GMT" "2004-02-02 GMT" "2004-02-02
> GMT"
> > Date2 = as.Date(Date2)
> > class(Date2)
> [1] "Date"
> > mode(Date2)
> [1] "numeric"
> > Date2
> [1] "2004-01-27" "2004-01-27" "2004-01-27" "2004-01-28" "2004-01-29"
> "2004-01-29" "2004-02-02" "2004-02-02"
> >
>
> ______________________________________________
> 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.
>
>
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