IF-Then logic with count and error=1 question

[mava]

Hi. I am studying for the base certification exam from the 5th edition of the Base Cert Prep book. 

I have a question about these examples that are in the book and I do not understand that the 

1. count+1 is counting

2. why an error=1 is in the statement 

I understand the conditions, though - just not those 2 statements.

Here are the codes for the 2 examples in which I am confused. 

I highlighted what I do not understand in blue.

Example 1:

if status='OK' and type=3

  then count+1;     (Does this count the number of type with the value 3? )

if (age ne agecheck or time ne3) and error=1 then Test=1;  (why is error=1 in there? I thought that was if there was at least one error in the program.

Question: What does the example 1 program? 

Example 2:

if (age ne agecheck or time ne 3)

     and error=1 then Test=1;   ( I don't understand why the error=1 is in there)

if status='S' or cond='E'

     then Control='Stop';     (I don't understand this one at all or am confused)

What does the example 2 program? What is it doing?

Thank you!   Mava

[Reeza]

COUNT+1 increments the count variable by 1. It's documented under the SUM statement.
https://documentation.sas.com/?cdcId=pgmsascdc&cdcVersion=9.4_3.5&docsetId=lestmtsref&docsetTarget=n...

Regarding your second question, I think you're mixing up the _error_ variable which is an automatic SAS variable. error in this case is a variable in the data set and the logic depends on context and needs.

[mava · Accepted solution]

Thanks!!!!

[Tom]

Both of these are just snippets of code. Not a full program. Or even a full data step.

What the meaning of the statements is depends on the context they are used in.  Including the data step they are running in.

In SAS the = is used for equality testing in boolean expressions (type=3) and in assignment statements (CONTROL='Stop'). The SAS compiler knows which you mean by the larger context of how you used them.

Your code snippets have three types of statements being used.

IF/THEN statement->  IF condition THEN statement ;

Assignment statement->  variable = expression; 

Sum statement-> variable + expression ; 

First question:

The IF/THEN statement means the value of COUNT is incremented by 1 when the condition tested is true.  So not just when TYPE=3 but also it is chekcing if STATUS='OK'. The fact that you used a SUM statement means that the variable COUNT will be retained across iterations of the data step instead of being reset to missing.

Second/Third question:

In this context ERROR is the name of variable, just like TYPE and STATUS and COUNT in the previous statement.  So the meaning of the test ERROR=1 depends on what it means for that variable to have that value.

Last question:

This statement is testing the values of the variable STATUS and COND and then conditionally changing the value of CONTROL to 'Stop'.

[mava]

Thank u

[mava]

Thank u so much!