Write specific values from a matrix to a data table

[ss59]

Hi all,

I have a nxn matrix (for simplicity assuming n=3) like following:

proc iml;
A = {0.1 0.2 0.5, 0.2 0.4 0.6, 0.2 0.3 0.8};

I have another table - a reference table, which specifies which values from this nxn (n=3) matrix needs to be written to a new data table. that table is following:

data output_table;
infile datalines dsd;
length FieldName $20 FieldSourceTable $20;
input Matrix_Id Row_Order Column_Order IsZero FieldName	FieldSourceTable;
datalines;
3,    1,   1,	1,	.,	.
3,    1,   2,	0,	result1,	table2
3,    1,   3,	0,	result2,	table2
3,    2,   1,	1,	.,		.
3,    2,   2,	0,	sum1,	table2
3,    2,   3,	0,	sum2,	table2
3,    3,   1,	0,	prod1,		table2
3,    3,   2,	0,	prod2,		table2
3,    3,   3,	1,	.,		.
;

Assume the matrix A is my Matrix_ID 3. So, I need to create a new table called table 2 with the names specified in 'FieldName' column in the reference table and write specific values from the matrix to the table (e.g. (1,2)th element to the column 'result1').

For this specific example, the output should look like:

result1	result2	sum1	sum2	prod1	prod2
0.2	0.5	0.4	0.6	0.2	0.3

How do I do this in iml? Thanks!

[ss59 · Accepted solution]

I've been able to figure this out:

proc sort data= output_table out= output_table;
by Row_Order Column_Order;
quit;

proc iml;
use output_table;  /* parameterization table for matrix 3 (output table)*/
read all var {Column_Order Row_Order FieldName};
close;

idx = loc(FieldName ^= " ");

refNames = FieldName[idx];

A = {0.1 0.2 0.5, 0.2 0.4 0.6, 0.2 0.3 0.8}; /*A is the full matrix to write*/

C = A[idx];
C = t(C);
mattrib C colname=refNames;

print C;

create data_to_write from C[colname = refNames];
append from C; /** create data set **/
close data_to_write;