topic Re: code problems in SAS Procedures

code problems

tz0715 — Tue, 01 Jul 2014 08:11:45 GMT

what does this code means?

(first.id and last.id)<1 and (first.id and last.id)<1"

<1 for what meanings?

part of the dataset:

id day1

1 2000/01/01

1 2001/12/15

1 2001/12/31

2 2005/03/04

2 2005/05/06

2 2006/07/09

2 2006/08/09

3 2008/01/15

3 2009/05/25

3 2009/07/15

thank you~

Re: code problems

RW9 — Tue, 01 Jul 2014 08:16:06 GMT

This means less than, i.e. if (first.id and last.id) is less than 1.

Sybols are:

< less than

> greater than

<= less than or equal to

>= greater than or equal to

There are several others in the SAS help.

Re: code problems

Ksharp — Tue, 01 Jul 2014 12:11:48 GMT

(first.id and last.id) only has two value either 0 or 1 . Therefore, (first.id and last.id)<1 is the same with (first.id and last.id)=0

Re: code problems

Astounding — Tue, 01 Jul 2014 13:11:58 GMT

Ksharp,

You solved my earlier riddle, so here's a new one related to this question. What does this statement do?

if a=1 or 2 then b=3 and c=4;

Yes, it will run without error. But what does it do?

Re: code problems

Ksharp — Tue, 01 Jul 2014 13:34:46 GMT

Hi, Astounding

That is an old scam . 2 is always be true , therefore a=1 or 2 is always be true too , you are going to execute the following statement always .Am I right ?

Xia Keshan

Re: code problems

Astounding — Tue, 01 Jul 2014 13:59:27 GMT

You're right about the IF condition. What about the THEN result?

Re: code problems

Ksharp — Tue, 01 Jul 2014 14:17:32 GMT

That is strange code , Can you explain it ?

Oh , I understood .

then b=(2 and c=2) ;

Re: code problems

ballardw — Tue, 01 Jul 2014 14:20:34 GMT

B is set to 0 (false) and if C doesn't exist you get a missing value for an uninitialized variable.

3 and c evaluates to false unless c = 4 then you get 3 and true (c=4) so true and true = true for B.

Re: code problems

Astounding — Tue, 01 Jul 2014 14:29:00 GMT

Good answer.

B will be 0 or 1, depending on the value of C. "3" is always true. So when C=4, B is set to 1. For any other value of C (including missing), B is set to 0.