Successively multiply values of lower part of a matrix with an array

[Nikos]

Hi all,

I would appreciate your help on the following.

I have two data sets (arrays)

Data X

V1	V2	V3	V4	V5
2	1	4	6	3
4	5	2	1
7	8	2
3	9
5

and Data Y

A1	A2	A3	A4	A5
2	1	3	5	6

I would like to fill the missing lower part of the matrix by successively multiplying the previous non-missing value of Data X with the elements of the Data Y

i.e. for the last observation  10= 5*2 (A1),  10= 10 * 1 (A2), 30=10* 3 (A3) , 150 = 30 * 5 (A4) and 900 = 150 * 6(A5)

Consequently column V_New will be created due to final multiplication.

So  Data Z is the desired one

V1	V2	V3	V4	V5	V_New
2	1	4	6	3	18
4	5	2	1	5	30
7	8	2	6	30	180
3	9	9	27	135	810
5	10	10	30	150	900

Thank you in advance.

Nik

[data_null__ · Accepted solution]

data v;
   infile cards expandtabs missover;
   input V1-V5;
   cards;
2  1  4  6  3
4  5  2  1 
7  8  2    
3  9       
5          
;;;;
   run;
proc print;
   run;
Data a;
   infile cards expandtabs;
   input A1-A5;
   cards;
2  1  3  5  6
;;;;
   run;
proc print;
   run;
data mult;
   if _n_ eq 1 then set a;
   set v;
   array v

v: Vx;

   array a

a:;

   do i = n(of v

);

      do j = i to dim(a);
         v[j+1] = a*v;
         end;
      end;
   drop i j;
   run;
proc print;
   run;

[Ksharp]

I like such kind of questions.

data v;
   infile cards expandtabs missover; 
   input V1-V5;
   cards; 
2  1  4  6  3
4  5  2  1  
7  8  2     
3  9        
5           
;;;;
   run; 
   Data a;
   infile cards expandtabs; 
   input A1-A5;
   cards; 
2  1  3  5  6
;;;;
   run; 
data want;
 if _n_ eq 1 then set a;
 set v;
 array x{*} v1-v5 v_new;
 array y{*} a1-a5;
 do i=1 to dim(x)-1;
   temp=x{i}*y{i};
   if missing(x{i+1}) then x{i+1}=temp;
 end;
 drop temp i a:;
run;

Xia Keshan