topic Re: create new variable using input and format in SAS Programming

create new variable using input and format

stataq — Wed, 03 Apr 2024 01:48:35 GMT

Hello,

I have a silly question. I saw people use proc format and then build new variable with it.

I saw some used

Region = put(parkcode, $reglbl.);

but some used

Region=put(parkcode, ??  reglbl.)

what are the difference. I am very confused on '??' part. Could anyone guide me on this?

Thanks.

Re: create new variable using input and format

Astounding — Wed, 03 Apr 2024 02:06:05 GMT

?? can be used with the INPUT function, not the PUT function. Consider these variations:

n1 = input('ABC', 3.);
n2 = input('ABC', ?? 3.);

The first statement would give you a message about invalid data being read since the 3. informat looks to create a numeric value. And "ABC" can't be read as numeric.

In a way, the second statement gives the same outcome in that n1 will equal n2. However, the ?? suppresses any messages in the log about invalid data.

Re: create new variable using input and format

stataq — Wed, 03 Apr 2024 02:27:50 GMT

Thanks. So "??" is for cleaner log file? when do we need to use "??" instead?

Re: create new variable using input and format

Tom — Wed, 03 Apr 2024 02:39:17 GMT

@stataq wrote:

Thanks. So "??" is for cleaner log file? when do we need to use "??" instead?

You don't NEED to use it.

You might WANT to use it when:

You know that some of the original values might not be valid for the INFORMAT being used.
You do not need to distinguish between those original values. They will be mapped to missing.
You do not want the SAS log to display the invalid values.