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Working on a DateListPlot in Mathematica 12.1, and I only want to label the last point in the resulting chart with the second value (the number of COVID-19 cases). How?

Here's the code I have thus far (minus the first line, which is a CloudConnect command to get the data.) The ResourceObject call in the first line below is an effort to force it to get the latest data.

resource = ResourceObject["Epidemic Data for Novel Coronavirus COVID-19"];
data = ResourceData["Epidemic Data for Novel Coronavirus COVID-19"][Select[MatchQ[Entity["Country","UnitedStates"],#Country]&&!MissingQ[#AdministrativeDivision]&]][GroupBy["Country"]][ All, Total, #ConfirmedCases &];
diffs = Differences[data[Entity["Country","UnitedStates"]]];
Export["/home/pi/Pictures/COVIDCharts.png",Row[{DateListPlot[data,PlotLabel->"Total COVID-19 Cases, U.S.", PlotRange->All,PlotTheme->"Detailed",ImageSize->Large,LabelingFunction->(# &)],
DateListPlot[diffs,PlotLabel->"Daily New Cases Reported, U.S.", PlotRange->All,PlotTheme->"Detailed",ImageSize->Large,LabelingFunction->(# &)]}]]

Image of the first chart

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  • $\begingroup$ Update to my own posting: I figured out using #[[2]] gives me just the second value (with a decimal point at the end); just now need to know how to only show the latest (last) value. $\endgroup$
    – Steven Buehler
    Commented Apr 18, 2020 at 2:25
  • $\begingroup$ Quite related ?mathematica.stackexchange.com/q/219501/1089 $\endgroup$
    – chris
    Commented Apr 18, 2020 at 10:17

1 Answer 1

Reset to default
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Row[{DateListPlot[data, 
   PlotLabels -> {Column @ {DateString @ First[Normal[Values[data]]] @ "LastTime", 
       First[Normal[Values[data]]] @ "LastValue"}}, 
   PlotLabel -> "Total COVID-19 Cases, U.S.", PlotRange -> All, 
   PlotTheme -> "Detailed", ImageSize -> 550], 
  DateListPlot[diffs, 
   PlotLabels -> {Column @ {DateString @ diffs @ "LastTime", diffs @ "LastValue"}}, 
   PlotLabel -> "Daily New Cases Reported, U.S.", PlotRange -> All, 
   PlotTheme -> "Detailed", ImageSize -> 550]}, Spacer[10]]

enter image description here

Or

label1 = Placed[Column@
  {DateString[#, {"MonthName", " ", "Day", ", ", "Year"}], #2} & @@ 
    (First[Normal[Values[data]]] /@ {"LastTime", "LastValue"}), After];

label2 = Placed[Column@
  {DateString[#, {"MonthName", " ", "Day", ", ",  "Year"}], #2} & @@ 
    (diffs /@ {"LastTime", "LastValue"}),  After];

Row[{DateListPlot[data, PlotLabels -> label1, 
   PlotLabel -> "Total COVID-19 Cases, U.S.", PlotRange -> All, 
   PlotTheme -> "Detailed", ImageSize -> 550], 
  DateListPlot[diffs, PlotLabels -> label2, 
   PlotLabel -> "Daily New Cases Reported, U.S.", PlotRange -> All, 
   PlotTheme -> "Detailed", ImageSize -> 550]}, Spacer[10]]

enter image description here

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2
  • $\begingroup$ This is the answer I'm looking for; but I need the layout of the first solution with the label format (date only) of the second; I'll keep pluggin'. :-) $\endgroup$
    – Steven Buehler
    Commented Apr 20, 2020 at 19:31
  • 1
    $\begingroup$ Figured it out, it's admittedly a kludge: StringReplace[DateString @ data @ "LastDate"," 12:00 am"->""] $\endgroup$
    – Steven Buehler
    Commented Apr 20, 2020 at 19:42

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