topic Re: What is in (.) mean? in SAS Programming

What is in (.) mean?

Nietzsche — Sun, 19 Mar 2023 12:16:13 GMT

trying to understand my mate's code. I have never seen this before but what does in (.) mean?

Re: What is in (.) mean?

Kurt_Bremser — Sun, 19 Mar 2023 12:19:56 GMT

if adj_fac not in (.)

is equal to

if adj_fac ne .

Maybe someone did not remember the mnemonic for "not equal" 😉

Re: What is in (.) mean?

Nietzsche — Sun, 19 Mar 2023 12:28:44 GMT

I see. why not just not missing? so much easier to read.

Re: What is in (.) mean?

PaigeMiller — Sun, 19 Mar 2023 13:19:11 GMT

not missing(adj_fac)

works too. There are many ways to do this.

Re: What is in (.) mean?

Kurt_Bremser — Sun, 19 Mar 2023 13:22:47 GMT

if adj_fac ne .

is less typing than

if not missing(adj_fac)

Good programmers are lazy (Linus Torvalds) 🙂

Re: What is in (.) mean?

Tom — Sun, 19 Mar 2023 16:56:32 GMT

They probably used to have other values in the list of excluded values.

if adj_fac not in (. 0 -1 999) then ...

And they removed the others and did not bother to change from the IN operator to equality operator once there was only one value left in the list.

Re: What is in (.) mean?

ballardw — Sun, 19 Mar 2023 18:35:08 GMT

@Nietzsche wrote:

I see. why not just not missing? so much easier to read.

For any question relating to "WHY" you must ask the programmer.

I can see a scenario where a prior version of the programming used a list of values with or without the missing. Then needs changed and the list was reduced or replaced leaving the . as the only list.

I have code where I have some code like " IN ('one value') " instead of "variable = 'one value' " because history has shown me that I am very likely to have to add values.

Re: What is in (.) mean?

yabwon — Sun, 19 Mar 2023 20:13:03 GMT

But those two are not equivalent.

1    data test;
2      adj_fac = .B;
3      if adj_fac ne . then x1=1;
4      if not missing(adj_fac) then x2=1;
5      put _all_;
6    run;

adj_fac=B x1=1 x2=. _ERROR_=0 _N_=1

Bart

Re: What is in (.) mean?

yabwon — Sun, 19 Mar 2023 20:16:05 GMT

..or:

if adj_fac > .z then ...

🙂

Bart

Re: What is in (.) mean?

tarheel13 — Sun, 19 Mar 2023 20:35:20 GMT

it means adj_fac was not missing. I wouldn't have written it that way. I prefer the missing function like others have mentioned here.