program loops and renumerative counting

[LB]

Hello all-

I have the following code below-

data uppy;

input spec $1. @3 pt 1.;

datalines;

a 0

a 0

a 0

a 1

a 1

a 1

;

run;

data upgraded_out;

set uppy;

by spec;

PTX=LAG(PT);

IF  FIRST.spec then do;

PTX=. ;

END;

UPGRADED=sum(PT,PTX);

run;

The results are as shown:

Obs	spec	pt	PTX	UPGRADED

	1	a	0	.	0
	2	a	0	0	0
	3	a	0	0	0
	4	a	1	0	1
	5	a	1	1	2
	6	a	1	1	2

The problem is observation 6-I would like the end result to be the total points -3;

I cannot simply sum the values in a proc sql statement as in the end I actually need to output where the upgrade value is only two.

Any assistance greatly appreciated.

Lawrence

[Steelers_In_DC]

Can you add some explanation of why it should be -3?  I don't understand what you are trying to do.

[LB]

Thanks Mark & Astounding! That works.

Mark-The final observation should have been 3 and not -3.  That was a typo.

In short I will explain-

What the zeros and ones represent are a patient's assessment in an ICU-

0 is not mobile, 1 is mobile. I have a physician who wants data on when a patient is mobile on the second assessment.

And I chose Mark's answer as correct as it was the first one posted (that worked)  but they both do the job! 

Lawrence

[Steelers_In_DC · Accepted solution]

This might help but I'm not sure what you are trying to accomplish:

data upgrade;

set uppy;

retain upgraded;

by spec pt;

if first.pt then upgraded = pt;

if not first.pt then upgraded = upgraded+pt;

run;

[Astounding]

It sounds like you need something very straightforward:

data upgraded_out;

set uppy;

by spec;

if first.spec then upgraded = pt;

else upgraded + pt;

run;

Is that the result you are looking for?

Mark ... same idea looks like you posted a minute before me!