Creating a somewhat unique ID using the UUIDGEN function

According to the Daily Writing Tips blog, describing a thing as “somewhat unique” is bad form. Unique means “one of a kind”, so either it is or it is not. The famous example (which the style police will use to chide you) is that you can’t have something as “somewhat unique” any more than a woman can be “somewhat pregnant”.

But when programming and dealing with computers, we often deal with the concept of “unique enough”. And to fill that niche, we have the Globally Unique Identifiers, or GUIDs. (Most people pronounce this “GOO-ids”.) These are also called UUIDs, for “universal unique identifiers”. (But the Universe is pretty big, isn’t it? Therefore using this term makes a pretty bold claim.)

A GUID is a 128-bit value, allowing for 2¹²⁸ (or 3.4028237e+38) possibilities. Computer processes generate GUIDs behind the scenes all of the time for lots of purposes, and among geeks we joke that they will become a scarce resource, like helium. But rest assured: it will take us a long time to go through all of the possible GUID values.

When we see GUID values in the wild, they are usually expressed as a series of 32 hexadecimal characters, often containing hyphens like a crazy sort of phone number (as if you might attempt to commit it to memory):

   efb40385-6b5c-4e7f-9f19-1daeb7e97ed9

I created the above GUID fresh for this blog (it’s never been seen before!) using a tool on my PC called uuidgen, which is part of the Windows SDK.

In the SAS world, I can use the UUIDGEN function to create these as needed from within my SAS program:

data wastedGuids;
do x=1 to 10;
  guid = uuidgen();
  output;
end;
run;

Result:

The UUIDGEN function relies on code libraries that are system-dependent, as there are different algorithms for creating GUID values. When I run the above program on a Linux version of SAS, I get a different pattern of results:

I suppose — now that I’ve promoted this function on the blog — we’ll have SAS programmers cranking GUIDs out day-and-night. At this rate, will there be any GUIDs left for our grandchildren? Well, I can’t worry about that — live for today, I say.

Bonus joke: How do you catch a unique rabbit? (Reply in the comments, please.)