Autofilling a list of dates in a specific range from partial dates in a column

[csanfor2]

I have a dataset with values by date and county. I want to look at rolling averages over time and compare them by county, but I think I need to back fill-in the dates between a specific range of values first. I want to all the dates from March 1 to March 6. If the date isn't currently there then the values should be set to 0. 

Can anyone help me find a way to do that?

data have; 
input county $ date :mmddyy10. value1 value2 total;
format date mmddyy10.;
datalines;
CountyA 03/02/2020 2 0 2
CountyA 03/03/2020 3 1 4
CountyA 03/05/2020 5 2 7
CountyB 03/02/2020 1 0 1
CountyB 03/04/2020 4 1 5
CountyB 03/06/2020 2 1 3
	;
run;


data want; 
input county $ date :mmddyy10. value1 value2 total;
format date mmddyy10.;
datalines;
CountyA 03/01/2020 0 0 0
CountyA 03/02/2020 2 0 2
CountyA 03/03/2020 3 1 4
CountyA 03/04/2020 0 0 0
CountyA 03/05/2020 5 2 7
CountyA 03/06/2020 0 0 0
CountyB 03/01/2020 0 0 0
CountyB 03/02/2020 1 0 1
CountyB 03/03/2020 0 0 0
CountyB 03/04/2020 4 1 5
CountyB 03/05/2020 0 0 0
CountyB 03/06/2020 2 1 3
	;
run;

[novinosrin · Accepted solution]

data have; 
input county $ date :mmddyy10. value1 value2 total;
format date mmddyy10.;
datalines;
CountyA 03/02/2020 2 0 2
CountyA 03/03/2020 3 1 4
CountyA 03/05/2020 5 2 7
CountyB 03/02/2020 1 0 1
CountyB 03/04/2020 4 1 5
CountyB 03/06/2020 2 1 3
	;
run;


%let start_date=01mar2020;
%let end_date=06mar2020;
data want;
 if _n_=1 then do;
  dcl hash H () ;
  h.definekey  ("date") ;
  h.definedata ("value1", "value2", "total") ;
  h.definedone () ;
 end;
 do until(last.county);
  set have;
  by county;
  h.add();
 end;
 do date="&start_date"d to "&end_date"d;
  value1=0;value2=0;total=0;
  _n_=h.find();
  output;
 end;
 h.clear();
run;

  

county	date	value1	value2	total
CountyA	03/01/2020	0	0	0
CountyA	03/02/2020	2	0	2
CountyA	03/03/2020	3	1	4
CountyA	03/04/2020	0	0	0
CountyA	03/05/2020	5	2	7
CountyA	03/06/2020	0	0	0
CountyB	03/01/2020	0	0	0
CountyB	03/02/2020	1	0	1
CountyB	03/03/2020	0	0	0
CountyB	03/04/2020	4	1	5
CountyB	03/05/2020	0	0	0
CountyB	03/06/2020	2	1	3

[Shmuel]

try next code:

data have; 
input county $ date :mmddyy10. value1 value2 total;
format date mmddyy10.;
datalines;
CountyA 03/02/2020 2 0 2
CountyA 03/03/2020 3 1 4
CountyA 03/05/2020 5 2 7
CountyB 03/02/2020 1 0 1
CountyB 03/04/2020 4 1 5
CountyB 03/06/2020 2 1 3
	;
run;

proc sort data=have; by county date; run;

data want;
 set have;
  by county;
     array dayx d1-d6;
	 if first.county then do 1 to 6;
	    dayx(i) = .;
     end;
     if not last.county then do;
        if date < '01jun2020'd or
		   date > '06jun2020'd then output;
		else dayx(day(date)) = 1;
	end;
	if last.county then do;
	   if '01jun2020'd le date le '06jun2020'd
	   then dayx(day(date)) = 1;
	   output;
	   do i=1 to 6;
	      if dayx(i) = 0 then do;
		     valu1=0; valu2=0; value3=0;
			 date = mdy(6,i,2020);
			 output;
		  end;
		end;
	end;
run;

proc sort data=have; by county date; run;