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

[Jeff Newmiller]

Don't set the header argument to TRUE if your data does not have a header?

On December 16, 2020 11:09:18 AM PST, Gregory Coats via R-help <r-help using r-project.org> wrote:
>I would like to be able to draw and label a vertical line, representing
>the date of some arbitrary event. The date of the first non-zero 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 00.000
>2013-12-29 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=TRUE,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="l", 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))
>
>
>	[[alternative HTML version deleted]]
>
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-- 
Sent from my phone. Please excuse my brevity.