I am new to R and have been struggling with the following problem. I apologize
if there is an obvious answer that I have missed.
I bring in a .txt file (pyr_h.txt) that has a DateTime column in the format
"yyyy-mm-dd HH:MM"
When it comes into R, R does not recognize it as a date/time format.
Date Time DateTime N_Wm2 S_Wm2
1 4/1/2008 01:00 2008-04-01 01:00 0.0000 0.00000
2 4/1/2008 02:00 2008-04-01 02:00 0.0000 0.00000
3 4/1/2008 03:00 2008-04-01 03:00 0.0000 0.00000
4 4/1/2008 04:00 2008-04-01 04:00 0.0000 0.00000
5 4/1/2008 05:00 2008-04-01 05:00 0.0000 0.00000
6 4/1/2008 06:00 2008-04-01 06:00 3.1655 2.56175
CODE:
pyr_h =
read.table("H:/MastersInfo/data/Figures/Tables/pyr_h.txt",header = T,
sep = "\t")
# convert Date to date format
pyr_h$Date = as.Date(pyr_h$Date, format = "%m/%d/%Y")
# convert DateTime to number format
pyr_h$DateTime = strptime(pyr_h$DateTime, format="%Y-%m-%d %H:%M")
This strptime command works on another .txt file of mine with the exact same
date/time stamps, but when I try it for this file, it gives the error message:
Error in `$<-.data.frame`(`*tmp*`, "DateTime", value = list(sec =
c(0, :
replacement has 9 rows, data has 1570
I tried creating a vector:
tmp <-strptime(pyr_h$DateTime, format="%m/%d/%Y %H:%M")
When I queried the length of this vector, it was 9, yet when I print the vector
there are 1570 objects.
Any idea what is going on here? I have tried formatting the DateTime different
ways in Excel, recreating the .txt file, changing the strptime format, and
rebooting R yet nothing seems to be working.
Thanks SO much!
Kara
Kara Przeczek
M.Sc. Candidate NRES - Environmental Science
University of Northern B.C.
3333 University Way
Prince George B.C V2N 4Z9
Phone: (250) 960-5427
przeczek at unbc.ca
strptime has output of a POSIXlt object and you want an POSIXct object, so use: as.POSIXct(strptime(.... On Fri, Nov 28, 2008 at 7:12 PM, Kara Przeczek <przeczek at unbc.ca> wrote:> I am new to R and have been struggling with the following problem. I apologize if there is an obvious answer that I have missed. > > I bring in a .txt file (pyr_h.txt) that has a DateTime column in the format "yyyy-mm-dd HH:MM" > When it comes into R, R does not recognize it as a date/time format. > > Date Time DateTime N_Wm2 S_Wm2 > 1 4/1/2008 01:00 2008-04-01 01:00 0.0000 0.00000 > 2 4/1/2008 02:00 2008-04-01 02:00 0.0000 0.00000 > 3 4/1/2008 03:00 2008-04-01 03:00 0.0000 0.00000 > 4 4/1/2008 04:00 2008-04-01 04:00 0.0000 0.00000 > 5 4/1/2008 05:00 2008-04-01 05:00 0.0000 0.00000 > 6 4/1/2008 06:00 2008-04-01 06:00 3.1655 2.56175 > > > CODE: > pyr_h = read.table("H:/MastersInfo/data/Figures/Tables/pyr_h.txt",header = T, sep = "\t") > # convert Date to date format > pyr_h$Date = as.Date(pyr_h$Date, format = "%m/%d/%Y") > # convert DateTime to number format > pyr_h$DateTime = strptime(pyr_h$DateTime, format="%Y-%m-%d %H:%M") > > This strptime command works on another .txt file of mine with the exact same date/time stamps, but when I try it for this file, it gives the error message: > > Error in `$<-.data.frame`(`*tmp*`, "DateTime", value = list(sec = c(0, : > replacement has 9 rows, data has 1570 > > I tried creating a vector: > > tmp <-strptime(pyr_h$DateTime, format="%m/%d/%Y %H:%M") > > When I queried the length of this vector, it was 9, yet when I print the vector there are 1570 objects. > Any idea what is going on here? I have tried formatting the DateTime different ways in Excel, recreating the .txt file, changing the strptime format, and rebooting R yet nothing seems to be working. > Thanks SO much! > Kara > > Kara Przeczek > M.Sc. Candidate NRES - Environmental Science > University of Northern B.C. > 3333 University Way > Prince George B.C V2N 4Z9 > Phone: (250) 960-5427 > przeczek at unbc.ca > > > > ______________________________________________ > R-help at 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. >-- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve?
You want to convert the datetime to POSIXct, not POSIXlt:> as.POSIXct("2005-12-20 12:45")[1] "2005-12-20 12:45:00 EST" See R News 4/1 for details. On Fri, Nov 28, 2008 at 7:12 PM, Kara Przeczek <przeczek at unbc.ca> wrote:> I am new to R and have been struggling with the following problem. I apologize if there is an obvious answer that I have missed. > > I bring in a .txt file (pyr_h.txt) that has a DateTime column in the format "yyyy-mm-dd HH:MM" > When it comes into R, R does not recognize it as a date/time format. > > Date Time DateTime N_Wm2 S_Wm2 > 1 4/1/2008 01:00 2008-04-01 01:00 0.0000 0.00000 > 2 4/1/2008 02:00 2008-04-01 02:00 0.0000 0.00000 > 3 4/1/2008 03:00 2008-04-01 03:00 0.0000 0.00000 > 4 4/1/2008 04:00 2008-04-01 04:00 0.0000 0.00000 > 5 4/1/2008 05:00 2008-04-01 05:00 0.0000 0.00000 > 6 4/1/2008 06:00 2008-04-01 06:00 3.1655 2.56175 > > > CODE: > pyr_h = read.table("H:/MastersInfo/data/Figures/Tables/pyr_h.txt",header = T, sep = "\t") > # convert Date to date format > pyr_h$Date = as.Date(pyr_h$Date, format = "%m/%d/%Y") > # convert DateTime to number format > pyr_h$DateTime = strptime(pyr_h$DateTime, format="%Y-%m-%d %H:%M") > > This strptime command works on another .txt file of mine with the exact same date/time stamps, but when I try it for this file, it gives the error message: > > Error in `$<-.data.frame`(`*tmp*`, "DateTime", value = list(sec = c(0, : > replacement has 9 rows, data has 1570 > > I tried creating a vector: > > tmp <-strptime(pyr_h$DateTime, format="%m/%d/%Y %H:%M") > > When I queried the length of this vector, it was 9, yet when I print the vector there are 1570 objects. > Any idea what is going on here? I have tried formatting the DateTime different ways in Excel, recreating the .txt file, changing the strptime format, and rebooting R yet nothing seems to be working. > Thanks SO much! > Kara > > Kara Przeczek > M.Sc. Candidate NRES - Environmental Science > University of Northern B.C. > 3333 University Way > Prince George B.C V2N 4Z9 > Phone: (250) 960-5427 > przeczek at unbc.ca > > > > ______________________________________________ > R-help at 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. >