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

[Bill Dunlap]

Have you tried
   abline(v=as.Date("2019-04-06"), col="red")

-Bill

On Fri, Dec 18, 2020 at 9:29 AM Gregory Coats <gregcoats using me.com> wrote:

> I need to be able to draw and label a vertical line, representing the date
> of some arbitrary event. The date of the first entry is 2013-11-29. How
> would I draw, and label a red vertical line at 2019-04-06? Greg
>
> gcdf<-read.table(text="2013-11-29 19.175
> 2014-01-20 10.072
> 2014-02-12 10.241
> 2014-03-02 05.916
> 2014-03-15 05.942
> 2014-03-23 03.639
> 2014-04-06 08.283
> 2014-04-20 07.323
> 2014-05-11 09.807
> 2014-05-30 10.398
> 2014-06-15 13.949
> 2014-07-06 13.840
> 2014-07-18 07.906
> 2014-07-21 13.609
> 2014-08-03 17.316
> 2014-08-10 09.585
> 2014-08-24 16.022
> 2014-09-07 15.403
> 2014-09-21 14.880
> 2014-10-08 18.950
> 2014-10-24 18.185
> 2014-11-03 10.178
> 2014-11-09 07.438
> 2014-11-23 16.053
> 2014-12-07 12.896
> 2014-12-21 18.306
> 2015-01-05 16.580
> 2015-01-18 14.603
> 2015-01-25 08.192
> 2015-02-08 15.690
> 2015-02-16 08.677
> 2015-03-08 15.493
> 2015-03-22 16.065
> 2015-04-05 15.990
> 2015-04-19 19.076
> 2015-04-26 11.310
> 2015-05-03 09.243
> 2015-05-10 13.366
> 2015-05-17 11.191
> 2015-05-25 12.329
> 2015-05-31 08.324
> 2015-06-07 12.985
> 2015-06-15 12.605
> 2015-06-21 09.759
> 2015-06-28 14.906
> 2015-07-05 09.106
> 2015-07-12 11.306
> 2015-07-19 10.052
> 2015-07-26 08.845
> 2015-08-02 11.634
> 2015-08-09 07.718
> 2015-08-16 06.057
> 2015-08-23 08.341
> 2015-08-30 06.702
> 2015-09-07 05.972
> 2015-09-13 08.249
> 2015-09-20 05.758
> 2015-10-05 13.772
> 2015-10-19 14.144
> 2015-11-03 14.305
> 2015-11-13 09.932
> 2015-11-20 17.418
> 2015-12-06 13.529
> 2015-12-20 15.440
> 2016-01-03 10.573
> 2016-01-19 09.592
> 2016-02-25 12.664
> 2016-04-03 18.993
> 2016-05-01 16.869
> 2016-06-07 15.012
> 2016-06-23 07.549
> 2016-06-27 13.756
> 2016-08-07 18.581
> 2016-09-01 11.334
> 2016-09-30 11.327
> 2016-11-06 18.018
> 2016-11-27 14.597
> 2016-12-04 15.347
> 2016-12-23 09.243
> 2017-01-05 16.035
> 2017-02-07 13.219
> 2017-02-19 16.196
> 2017-03-12 07.436
> 2017-05-08 19.747
> 2017-06-29 19.503
> 2017-08-15 19.676
> 2017-09-08 15.558
> 2017-10-17 16.705
> 2017-12-06 14.876
> 2018-01-12 13.748
> 2018-03-15 19.139
> 2018-04-13 19.056
> 2018-05-20 17.756
> 2018-06-02 15.631
> 2018-06-17 14.049
> 2018-07-05 18.870
> 2018-07-22 16.654
> 2018-08-06 17.171
> 2018-08-26 20.139
> 2018-09-09 18.442
> 2018-09-26 18.646
> 2018-10-14 17.144
> 2018-11-02 19.508
> 2018-11-20 12.454
> 2018-12-04 09.355
> 2018-12-14 09.152
> 2019-01-11 10.998
> 2019-02-02 07.739
> 2019-02-19 09.891
> 2019-03-22 18.716
> 2019-04-30 18.880
> 2019-06-03 19.247
> 2019-07-07 18.289
> 2019-08-30 19.021
> 2019-09-29 15.892
> 2019-10-26 18.180
> 2019-11-17 17.693
> 2019-12-08 16.528
> 2020-01-05 15.973
> 2020-02-15 18.832
> 2020-03-10 17.392
> 2020-05-04 14.774
> 2020-06-21 19.248
> 2020-08-01 14.913
> 2020-08-27 15.226
> 2020-09-28 14.338
> 2020-11-09 18.777
> 2020-12-11 19.652",
> header=FALSE,stringsAsFactors=FALSE,
> col.names=c("date","gallons"))
> gcdf$date<-as.Date(gcdf$date,"%Y-%m-%d")
> grid_dates<-as.Date(paste(2013:2021,1,1,sep="-"),"%Y-%m-%d")
> plot   (gcdf$date, gcdf$gallons, ylab="Refueling Gallons",
> xlab="",type="b", col="blue", yaxt="n")
> mtext  (side=3, line="+0", "2014 Toyota 4Runner")
> abline (h=seq(4,20,by=2), lty=3)
> abline (v=grid_dates, lty=4)
> axis   (side=2, at=seq(4,20,by=2))
>
>

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