topic Re: matrix cells calculation in SAS Programming

matrix cells calculation

Jonison — Fri, 24 Jul 2020 12:23:36 GMT

Hello, expert, I have a matrix

ID	col2	col3	col4
1	0.2543	0.376363	0.306857
2	0.010651	0.259333	0.073882
3	0.371874	0.258592	0.634631
4	-0.22921	0.084731	-0.39482
5	0.520023	0.553674	0.360524

can you please suggest how to do calculation for a set of cells in the table.

For example, calculate the average and std of row 2 and column 3 and 4, e.g. [2, 3:4].

Many thanks, is there any procedure would have such function?

Re: matrix cells calculation

PeterClemmensen — Fri, 24 Jul 2020 12:39:27 GMT

Do you have SAS/IML?

Re: matrix cells calculation

Jonison — Fri, 24 Jul 2020 12:41:46 GMT

Thanks, I think I have the SAS/IML.

Re: matrix cells calculation

PaigeMiller — Fri, 24 Jul 2020 12:57:32 GMT

Does this have to be done in a matrix, or can it be done in a SAS data step? Is it always columns 3 and 4 that is of interest, or can that change depending on various different circumstances?

Please don't say "I think I have...", please say either: you have it or you do not have it.

Re: matrix cells calculation

Jonison — Fri, 24 Jul 2020 13:00:19 GMT

would you please show me some example of using IML to do calculation? not familiar the syntax,

Thanks

Re: matrix cells calculation

Jonison — Fri, 24 Jul 2020 13:02:29 GMT

the column number is fixed always ID, x,x1-x7,

but the row number will change, due the updating database on daily basis.

Thanks.

Re: matrix cells calculation

Ksharp — Sat, 25 Jul 2020 12:45:58 GMT

Something like this:

data have;
 set sashelp.class;
 a=1;b=2;c=3;
run;

%let row=2;
%let col=2:5 ;
proc iml;
use have;
read all var _num_ into x;
close; 	

avg=mean(colvec(x[&row,&col]));
std=std(colvec(x[&row,&col]));

print avg,std;
quit;

Re: matrix cells calculation

Tom — Sun, 26 Jul 2020 13:59:02 GMT

Do you have a "matrix" or a dataset? Assuming you have a dataset then you are asking for:

data want;
  set have;
  where id = 2 ;
  avg = mean(of col3 col4);
  std = std(of col3 col4);
run;

Re: matrix cells calculation

PaigeMiller — Sun, 26 Jul 2020 15:41:29 GMT

@Jonison wrote:

the column number is fixed always ID, x,x1-x7,

but the row number will change, due the updating database on daily basis.

How does the programmer know which columns and rows to use for computing the mean?

Re: matrix cells calculation

Jonison — Sun, 26 Jul 2020 16:47:38 GMT

Thanks for your kind help, it is really useful and works perfectly.