topic Re: Macro logic for a value between 2 numbers in SAS Programming

Macro logic for a value between 2 numbers

kmorrowvt — Wed, 20 Mar 2013 13:10:27 GMT

I'm trying to figure out why this macro logic is working in this way:

%let bwgt=50;

%macro test;

%if 0 lt &bwgt and &bwgt lt 50 %then %put test1;

%if 0 lt &bwgt lt 50 %then %put test2;

%mend test;

%test;

This returns test2.

Why is it returning this when bwgt=50?

Obviously I can just write my code with an "and" and get around this issue, but I'm curious as to why this is happening

Thanks,

Kate

Re: Macro logic for a value between 2 numbers

Astounding — Wed, 20 Mar 2013 13:27:18 GMT

Unlike a DATA step, macro language does not process this as two separate comparisons:

0 lt &bwgt lt 50

Instead, macro language processes from left to right, as if you had coded:

(0 lt &bwgt) lt 50

Like a DATA step, macro language replaces true comparisons with a 0 and false comparisons with a 1. Since both 0 and 1 are less than 50, you will always get "test2" for any numeric value of &bwgt even if it's 55.

Good job on prodding, exploring, and asking.

Re: Macro logic for a value between 2 numbers

LinusH — Wed, 20 Mar 2013 13:41:38 GMT

Can't fins any references in documentation to that you can use the same between and logic with %if (as you can with if in the data step). But I can't explain why this is happening. You wanted this test to come up as false, right?

Re: Macro logic for a value between 2 numbers

kmorrowvt — Wed, 20 Mar 2013 13:52:39 GMT

Right since bwgt is not gt 0 and lt 50.