Dear Greg, There is no variable named Y_Var in your data set. I suspect that it's intended to be a generic specification in the recipe you were apparently given. In fact, there appears to be only one variable in myDat and that's datetime. What is it that you're trying to do? A more general comment: If I'm correct and you're just following a recipe, that's a recipe for problems. You'd probably be more successful if you tried to learn how ggplot(), etc., work. My apologies if I'm misinterpreting the source of your difficulties. I hope this helps, John John Fox, Professor Emeritus McMaster University Hamilton, Ontario, Canada web: https://socialsciences.mcmaster.ca/jfox/
On 2021-03-16 12:21 p.m., Gregory Coats via R-help wrote:
Sarah, Thank you. Yes, now as.POSIXct works. But the ggplot command I was told to use yields an Error message, and there is no output plot. Please help me. Greg
library(ggplot2) myDat <- read.table(text =
+ "datetime + 2021-03-11 10:00:00 + 2021-03-11 14:17:00 + 2021-03-12 05:16:46 + 2021-03-12 09:17:02 + 2021-03-12 13:31:43 + 2021-03-12 22:00:32 + 2021-03-13 09:21:43", + sep = ",", header = TRUE)
head(myDat)
datetime 1 2021-03-11 10:00:00 2 2021-03-11 14:17 3 2021-03-12 05:16:46 4 2021-03-12 09:17:02 5 2021-03-12 13:31:43 6 2021-03-12 22:00:32
myDat$datetime <- as.POSIXct(myDat$datetime, tz = "", format ="%Y-%M-%d %H:%M:%OS?) ggplot(myDat, aes(x=datetime, y = Y_Var)) + geom_point()
Error in FUN(X[[i]], ...) : object 'Y_Var' not found
On Mar 16, 2021, at 9:36 AM, Sarah Goslee <sarah.goslee at gmail.com> wrote: Hi, It doesn't have anything to do with having a Mac - you have POSIX. It's because something is wrong with your data import. Looking at the head() output you provided, it looks like your data file does NOT have a header, because there's no datetime column, and the column name is actually X2021.03.11.10.00.0 So you specified a nonexistent column, and got a zero-length answer. With correct specification, the as.POSIXct function works as expected on Mac: myDat <- read.table(text = "datetime 2021-03-11 10:00:00 2021-03-11 14:17:00 2021-03-12 05:16:46 2021-03-12 09:17:02 2021-03-12 13:31:43 2021-03-12 22:00:32 2021-03-13 09:21:43", sep = ",", header = TRUE) myDat$datetime <- as.POSIXct(myDat$datetime, tz = "", format = "%Y-%M-%d %H:%M:%OS") Sarah On Tue, Mar 16, 2021 at 9:26 AM Gregory Coats via R-help <r-help at r-project.org> wrote:
My computer is an Apple MacBook. I do not have POSIX. The command myDat$datetime <- as.POSIXct(myDat$datetime, tz = "", format = "%Y-%M-%d %H:%M:%OS") yields the error Error in `$<-.data.frame`(`*tmp*`, datetime, value = numeric(0)) : replacement has 0 rows, data has 13 Please advise, How to proceed? Greg Coats
library(ggplot2)
# Read a txt file on the Desktop, named "myDat.txt"
myDat <- read.delim("~/Desktop/myDat.txt", header = TRUE, sep = ",")
head(myDat)
X2021.03.11.10.00.00 1 2021-03-11 14:17:00 2 2021-03-12 05:16:46 3 2021-03-12 09:17:02 4 2021-03-12 13:31:43 5 2021-03-12 22:00:32 6 2021-03-13 09:21:43
# convert data to date time object myDat$datetime <- as.POSIXct(myDat$datetime, tz = "", format = "%Y-%M-%d %H:%M:%OS")
Error in `$<-.data.frame`(`*tmp*`, datetime, value = numeric(0)) : replacement has 0 rows, data has 13
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-- Sarah Goslee (she/her) http://www.numberwright.com
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______________________________________________ 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.