topic Re: ds2 loop practise question in SAS Academy for Data Science

ds2 loop practise question

Daniel121181 — Tue, 10 Mar 2020 08:10:57 GMT

Hello,

I was provided with this practise exam question (image below) and cannot understand why the given answer is not:

Total B=3; GrandTot=104. Indeed the answer given was Total B=4; GrandTot=104 which is confusing me.

After the loop has completed, wouldn't Total B = 3? The Grand total will then be 101+3=104?

Would be most grateful for some advice on this.

Thank you kindly.

Re: ds2 loop practise question

RichardDeVen — Tue, 10 Mar 2020 13:21:16 GMT

That is expected behavior. When the index variable is step adjusted to fall outside the DO range the loop is terminated. In this case the step adjustment (BY value) is implicitly +1 because there is no explicit BY.

The GRANDTOT computation is done before the DO statement steps in the index variable TOTALB past the TO value (3), So you get GRANDTOT 104 and TOTALB 4.

The DS2 "DO Statement" reference documentation for TO stop covers the concept in detail:

Execution continues based on the value of increment until one of the following conditions is met: the value of index-variable passes the value of stop, ...

FWIW, horrible coding in this practice question, would not pass code review.

Re: ds2 loop practise question

Daniel121181 — Tue, 01 Jun 2021 04:49:32 GMT

Thank you very much for your answer Richard and apologies for the delay in replying.