How to BLOCK Correctly in SGPLOT SERIES?

[Junyong]

SGPLOT Procedure BLOCK Statement shows the following image with blocks around dots—for example, the observation for Janet is located in the middle of the second red box.

I use both SERIES and BLOCK as follows—as a working example, 12 observations from January to December 2020 are displayed. A dummy variable equals one only in February and zero otherwise. The outcome, unlike the plot above, draws the February block after the second dot.

As in the first, I want the block in the middle rather than on the right of the dot. In this case, how can I relocate the block? The following is the MWE code.

data i;
	do i=1 to 12;
		t=mdy(i,1,2020);
		x+rannor(1);
		y=i=2;
		output;
	end;
run;

data j;
	input id :$ value fillcolor :$ filltransparency @@;
cards;
i 0 black 1 i 1 black 0.9
;

ods results=off;
ods listing gpath="!userprofile\desktop";
ods graphics/reset;

proc sgplot data=i dattrmap=j;
	series x=t y=x;
	block x=t block=y/attrid=i nooutline novalues;
	xaxis valuesformat=yymmddn6.;
quit;

ods graphics/reset;
ods listing gpath=none;
ods results=on;

[ChrisNZ]

You could make your variable a string:

T = put(mdy(I,1,2020),yymmdd.);

[Rick_SAS · Accepted solution]

Add the points that you want to use as the boundary of the block region. Then create a binary variable that indicates whether t is in the region that you want to shade. For example, the following program uses 15Jan and 15Feb as boundary values:

%let Left  = mdy(1,15,2020);
%let Right = mdy(2,15,2020);

data i;
	do i=1 to 12;
		t=mdy(i,1,2020);
		x+rannor(1);
		output;
	end;
run;
/* add points at boundary of block */
data Block;
t = &Left;  output;
t = &Right; output;
run;
/* merge boundary values and then sort */
data All;
merge i Block;
by t;
BlockID = (t>=&Left & t<&Right);
format t DATE9.;
run;

proc sort data=All; by t; run;

data j;
	input id :$ value fillcolor :$ filltransparency @@;
cards;
i 0 black 1 i 1 black 0.9
;

proc sgplot data=All dattrmap=j;
	series x=t y=x;
	block x=t block=blockID /attrid=i nooutline novalues;
	xaxis valuesformat=yymmddn9.;
quit;