How to update multiple columns based on one column value

[maysha2854]

Suppose I have 2 dates column. If I take difference of date I get months, the difference of two dates is 2months. 

I want to update column Month1-Month11 as 1 and 0 for other columns(Month12-Month24=0).

I tried using array but it updated only column Month11 as 1. I want to update all columns before Month12(Month1-Month11)

Thank you in advance.

[maysha2854]

Suppose I have 2 dates column. If I take difference of date I get months, the difference of two dates is 12months.

I want to update column Month1-Month11 as 1 and 0 for other columns(Month12-Month24=0).

I tried using array but it updated only column Month11 as 1. I want to update all columns before Month12(Month1-Month11)



Thank you in advance.

[PaigeMiller]

Please explain in more detail. Show us a small example. Show us the desired output from the small example. Show us the code you tried that didn't work.

[maysha2854]

Date1 Date2 Diff M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11 M12
Dec-19 Aug-20 8 . . . . . . . . . . . .
Sep-19 Mar-20 6 . . . . . . . . . . . .



Output

Date1 Date2 Diff M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11 M12
Dec-19 Aug-20 8 1 1 1 1 1 1 1 0 0 0 0 0
Sep-19 Mar-20 6 1 1 1 1 1 0 0 0 0 0 0 0



My Approach

data want
set have
array a1(8) month1-Month7
array a2(6) Month1-Month5
if Date_Diff =8 then a1(8) =1;
if Date_Diff =6 then a2(6) =1;
run;

[maysha2854]

My Approach

data want
set have
array a1(7) month1-Month7
array a2(5) Month1-Month5
if Date_Diff =8 then a1(7) =1;
if Date_Diff =6 then a2(5) =1;
run;

[PaigeMiller · Accepted solution]

data want;
    set have;
    array m m1-m12;
    do i=1 to dim(m);
        if i<diff then m(i)=1;
        else m(i)=0;
    end;
run;

[maysha2854]

You are the man