Diabetes: Prediction using discrimination on PCA - sql

Question

I have a table:
col1 col2
2 20
2.5 25
2.67 30
2.99 40
I'm looking to get
varone = 2 x col2, vartwo= 2.5 x col2, varthree= 2.67 x col3, varfour=2.99 x col2
i.e. extracting a specific value from a table
and then multiplying an entire column by that value (scalar x vector).
I tried transposing col1
col1a col1b col1c col1d col2
2 2.5 2.67 2.99 20
25
30
40
and then tried multiplying col1a x col2, but it didn't seem to work.

Answer 1

In SAS, you can just use proc sql:
proc sql;
select 2*col2 as varone, 2.5*col2 as vartwo, 2.67*col3 as varthree, 2.99*col2 as varfour
from atable;

Answer 2

Assuming you're using SAS and either PROC FACTOR or PROC PRINCOMP then you can use PROC SCORE.
Example straight from the documentation:
http://support.sas.com/documentation/cdl/en/statug/63347/HTML/default/viewer.htm#statug_score_sect017.htm
/* This data set contains only the first 12 observations */
/* from the full data set used in the chapter on PROC REG. */
data Fitness;
input Age Weight Oxygen RunTime RestPulse RunPulse ##;
datalines;
44 89.47 44.609 11.37 62 178 40 75.07 45.313 10.07 62 185
44 85.84 54.297 8.65 45 156 42 68.15 59.571 8.17 40 166
38 89.02 49.874 9.22 55 178 47 77.45 44.811 11.63 58 176
40 75.98 45.681 11.95 70 176 43 81.19 49.091 10.85 64 162
44 81.42 39.442 13.08 63 174 38 81.87 60.055 8.63 48 170
44 73.03 50.541 10.13 45 168 45 87.66 37.388 14.03 56 186
;
proc factor data=Fitness outstat=FactOut
method=prin rotate=varimax score;
var Age Weight RunTime RunPulse RestPulse;
title 'Factor Scoring Example';
run;
proc print data=FactOut;
title2 'Data Set from PROC FACTOR';
run;
proc score data=Fitness score=FactOut out=FScore;
var Age Weight RunTime RunPulse RestPulse;
run;
proc print data=FScore;
title2 'Data Set from PROC SCORE';
run;

Answer 3

You can make use of array to achieve this.
Below program is dynamic. It will work for any number of observations.
****data we have****;
data have;
input col1 col2;
datalines;
2 20
2.5 25
2.67 30
2.99 40
;
run;
****Taking Count****;
****Creating macro "value" to store col1 data****;
proc sql ;
select count(*) into :cnt_rec from have;
select col1 into :value1 - :value&SysMaxLong from have;
quit;
data want(drop=i);
set have;
array NewColumn(&cnt_rec);
****processing the array and multiplying col2 data****;
do i = 1 to &cnt_rec;
NewColumn[i] = symget('value'||left(i)) * col2;
end;
run;