[R] How to specify year-month-day for a plot

[Bill Dunlap]

You didn't show the entire call to read.table.  If it included the argument
header=TRUE then it would make the first entry in each column the name of
the column.  Use header=FALSE (or omit the header argument) if you don't
want the first entry to be considered the column name.

-Bill

On Wed, Dec 16, 2020 at 10:25 AM Gregory Coats via R-help <
r-help using r-project.org> wrote:

> I added a zero initial entry to the data set. Greg
> gcdf<-read.table(text="2013-11-29 00.000
> 2013-12-29 19.175
> 2014-01-20 10.072
> 2014-02-12 10.241
> 2014-03-02 05.916
>
> > On Dec 16, 2020, at 12:32 PM, Gregory Coats via R-help <
> r-help using r-project.org> wrote:
> >
> > Jim, Thank you!
> > The data set begins
> > gcdf<-read.table(text="2013-12-29 19.175
> > 2014-01-20 10.072
> > 2014-02-12 10.241
> > I note that data begins in 2013. But the plot command does not show this
> first entry in 2013, and instead shows the second data pair as the first
> data pair. As a consequence, plot does not show the first data pair for
> 2013, and begins in 2014.
> > Greg
> >
> >> On Dec 16, 2020, at 1:08 AM, Jim Lemon <drjimlemon using gmail.com> wrote:
> >>
> >> Hi Greg,
> >> I think this does what you want:
> >>
> >> gcdf$date<-as.Date(gcdf$date,"%Y-%m-%d")
> >> grid_dates<-as.Date(paste(2014:2020,1,1,sep="-"),"%Y-%m-%d")
> >> plot(gcdf$date, gcdf$gallons, main="2014 Toyota 4Runner", xlab="Date",
> >> ylab="Gallons",type="l",col="blue",yaxt="n")
> >> abline(h=seq(4,20,by=2),lty=4)
> >> abline(v=grid_dates,lty=4)
> >> axis(side=2,at=seq(4,20,by=2))
> >>
> >> Jim
> >>
> >> On Wed, Dec 16, 2020 at 2:16 PM Gregory Coats <gregcoats using me.com> wrote:
> >>>
> >>> Jim, Thanks for your help with R.
> >>> Feeding into R the file R_plot_18.r yields for me, on my Mac,
> R_plot_18.pdf. Success.
> >>> I used abline to draw a horizontal background grid, and then used axis
> label to identify the values represented by the horizontal dashed
> background lines.
> >>> abline (h=c(2,4,6,8,10,12,14,16,18,20,22,24), lty=4, lwd=1.0,
> col="grey60")
> >>> Similarly, I would like to draw a dashed vertical background grid. But
> it is unclear to me how to direct R to draw a vertical dashed background
> grid because I am again baffled how to specify to R a date value such as
> 2018-10-20 @18:00. I welcome your guidance.
> >>> Greg
> >>>
> >>> On Dec 13, 2020, at 10:58 PM, Jim Lemon <drjimlemon using gmail.com> wrote:
> >>>
> >>> Hi Gregory,
> >>>
> >>> On Mon, Dec 14, 2020 at 12:34 PM Gregory Coats <gregcoats using me.com>
> wrote:
> >>>
> >>> ...
> >>> Is there a convenient way to tell R to interpret “2020-12-13” as a
> date?
> >>>
> >>> Notice the as.Date command in the code I sent to you. this converts a
> >>> string to a date with a resolution of one day. If you want a higher
> >>> time resolution, use strptime or one of the other POSIX date
> >>> conversion functions.
> >>>
> >>> Jim
>
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