Do .... Until

[riskassure]

In SAS Programming, is there such a syntax

Do.... Until ?

In my example, I want to run a SAS macro repeatedly until the value in a certain table is equal to 0. How would I go about doing that?

Thanks in advance,

Chi

 

[ChrisW75]

Check out

http://v8doc.sas.com/sashtml/

do a search on "until".
Make sure you read carefully the sections entitled "Details" and "Comparisons". Do Until will always execute once, so if the first iteration has a value of 0, it'll execute once then move on. You may want to use Do While(value NE 0) instead.

You can also use %DO %UNTIL in a macro step which may suit you better, depending on the source of your counter.
Enjoy.

 

[riskassure]

Thanks ChrisW75!

I got most of it now, using a second macro, which includes %DO %WHILE to run my first macro repeatedly, depending on the counter. However, I am having some problems with this counter, because it's running on an infinite loop.

What I want is to use a %let counter = n somewhere. The n will be the value in a table that is generated as a result of the first macro. So, everytime this first macro is re-run, the table will be generated with a "smaller" n, etc.... Then, the second macro will look at this counter and decide if it should continue or not.

Do you know how this can be achieved?

Thanks in advance!

CW

 

[ChrisW75]

Sorry, no idea what you are trying to do. Let me know what you actually need at the end of the process (and what you have at the start) and I'll have a go.
Cheers.

 

[riskassure]

I think I may have figured this out. I was trying to pass a value found in a table to a variable that will be used as a counter in a do... while.... statement. However, this value changes everytime I run a macro. Everytime i run the macro the value decreases, until it reaches 0, and then the do... while... loop stops.

So, in my macro, I have

%macro abc;
blah blah blah... and something is done to Table xyz containing the value I want to use as a counter.
data xyz;
call symput("counter", n);
run;
blah blah blah...
%mend abc;

where counter is the name of my variable and n is the field in Table xyz containing the value I want to use for my counter.

Then, i have another macro that keeps running macro abc until counter = 0:

%macro efg;
%do %while (&counter ne 0);
%abc;
%end;
%mend efg;

Finally, my original code will simply run the macro efg to finish the job:

blah blah blah....
%efg;
blah blah blah....

I don't know if this is the most efficient way. But so far, it seems to work.

Thanks for you help though.

CW

 

[ChrisW75]

Sounds like a pretty smooth method. Can't see an immediate way of making it simpler. Good job!