topic Re: What does this code do? What is purpose of data _null_;? Can we this converted into Proc SQL? in SAS Programming

What does this code do? What is purpose of data _null_;? Can we this converted into Proc SQL?

GN0001 — Thu, 06 May 2021 05:17:03 GMT

%macro Mylist();
*Create Loop;

%let totalofRecords =0;

Data mydata;
set readfromMyolddata nobs=nobs;
Run;

data _null_ ;
set  mydata  nobs=nobs;
call symput('totalofRecords', compress(nobs));
put nobs;
stop;
run;

 %do i = 1 %to &totalofRecords.;

data _null_;
set mydata ;
if _n_ = &i;
call symput ('abc_file', compress (abc_file));
run;

%mend;

Blue Blue

Re: What does this code do? What is purpose of data _null_;? Can we this converted into Proc SQL?

Kurt_Bremser — Thu, 06 May 2021 05:37:32 GMT

@GN0001 wrote:

%macro Mylist();
*Create Loop;

%let totalofRecords =0;

Data mydata;
set readfromMyolddata nobs=nobs;
Run;

data _null_ ;
set  mydata  nobs=nobs;
call symput('totalofRecords', compress(nobs));
put nobs;
stop;
run;

 %do i = 1 %to &totalofRecords.;

data _null_;
set mydata ;
if _n_ = &i;
call symput ('abc_file', compress (abc_file));
run;

%mend;

Blue Blue

As posted, this code does nothing except throwing a syntax ERROR. Read the log (Maxim 2), and fix the obvious problem first.

Consult the documentation (Maxim 1) of the DATA Statement to see what _NULL_ does.

Re: What does this code do? What is purpose of data _null_;? Can we this converted into Proc SQL?

GN0001 — Thu, 06 May 2021 17:07:10 GMT

Hello,
Thanks for the response.
I can't see the obvious problem.
Documentations are very convoluted most of the time and it is hard to understand.
Respectfully,
Blue Blue

Re: What does this code do? What is purpose of data _null_;? Can we this converted into Proc SQL?

Kurt_Bremser — Thu, 06 May 2021 17:29:39 GMT

Post the logs, and I will show you the problem and the reason.

The documentation has to be what it is because the software is extremely powerful. You need to start working with it, as it is the number one tool for success with SAS. 90% of my posts here consist of reading the doc for things I don't use regularly in my day-to-day work.

Re: What does this code do? What is purpose of data _null_;? Can we this converted into Proc SQL?

GN0001 — Thu, 06 May 2021 22:41:46 GMT

This is my log:
1 OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK;
72
73 %macro Mylist();
74 *Create Loop;
75
76 %let totalofRecords =0;
77
78 Data mydata;
79 set readfromMyolddata nobs=nobs;
80 Run;
81
82 data _null_ ;
83 set mydata nobs=nobs;
84 call symput('totalofRecords', compress(nobs));
85 put nobs;
86 stop;
87 run;
88
89 %do i = 1 %to &totalofRecords.;
90
91 data _null_;
92 set mydata ;
93 if _n_ = &i;
94 call symput ('abc_file', compress (abc_file));
95 run;
96
97 %mend;
ERROR: There were 1 unclosed %DO statements. The macro MYLIST will not be compiled.
ERROR: A dummy macro will be compiled.
98

Regards,
Blue Blue

Re: What does this code do? What is purpose of data _null_;? Can we this converted into Proc SQL?

Patrick — Thu, 06 May 2021 23:26:54 GMT

The error tells you: ERROR: There were 1 unclosed %DO statements. The macro MYLIST will not be compiled.

You have to add a macro %end; statement at the highlighted location below

Even if this macro becomes syntactically correct it doesn't look to me like doing much useful things but it certainly does unnecessary and wasteful things.

What is the purpose of this macro? What does it get used for?

Re: What does this code do? What is purpose of data _null_;? Can we this converted into Proc SQL?

GN0001 — Thu, 06 May 2021 23:30:18 GMT

1 OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK;
72
73 %macro Mylist();
74 *Create Loop;
75
76 %let totalofRecords =0;
77
78 Data mydata;
79 set readfromMyolddata nobs=nobs;
80 Run;
81
82 data _null_ ;
83 set mydata nobs=nobs;
84 call symput('totalofRecords', compress(nobs));
85 put nobs;
86 stop;
87 run;
88
89 %do;
90 %i = 1 %to &totalofRecords.;
ERROR: Improper use of macro reserved word TO.
91
92 data _null_;
93 set mydata ;
94 if _n_ = &i;
95 call symput ('abc_file', compress (abc_file));
96 run;
97 end;
98 %mend;
ERROR: There were 1 unclosed %DO statements. The macro MYLIST will not be compiled.
ERROR: A dummy macro will be compiled.
99
100 ;
101
102 OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK;
114

Regards,
blue blue;

Re: What does this code do? What is purpose of data _null_;? Can we this converted into Proc SQL?

GN0001 — Thu, 06 May 2021 23:31:57 GMT

That is why I asked what it does.
Thanks,
Blue Blue

Re: What does this code do? What is purpose of data _null_;? Can we this converted into Proc SQL?

Patrick — Thu, 06 May 2021 23:33:56 GMT

Now you made your code even worse.

1. remove the semicolon after the %do

2. the end is on macro level and requires a %. It needs to be %end;

Re: What does this code do? What is purpose of data _null_;? Can we this converted into Proc SQL?

Kurt_Bremser — Fri, 07 May 2021 04:49:25 GMT

So what do you think this message:

ERROR: There were 1 unclosed %DO statements.

tries to tell you?

Hint: study the documentation of the %DO Statement.

Re: What does this code do? What is purpose of data _null_;? Can we this converted into Proc SQL?

Patrick — Fri, 07 May 2021 08:00:29 GMT

@GN0001 wrote:
That is why I asked what it does.
Thanks,
Blue Blue

Sorry but the answer to such a generic question must be RTM.

"Explain me everything" starting with "how does SAS work" is may be a bit too much for this forum here.

Re: What does this code do? What is purpose of data _null_;? Can we this converted into Proc SQL?

GN0001 — Fri, 07 May 2021 15:47:24 GMT

%end? Or %mend?

Thanks,

blue blue

Re: What does this code do? What is purpose of data _null_;? Can we this converted into Proc SQL?

Kurt_Bremser — Fri, 07 May 2021 16:43:36 GMT

The first example in the documentation I linked has a complete example of a %DO loop, use it as a blueprint to avoid the simple mistakes.

Re: What does this code do? What is purpose of data _null_;? Can we this converted into Proc SQL?

GN0001 — Fri, 07 May 2021 23:39:36 GMT

Hello KurtBremser,
I have no idea where you are referring to.
On documentation, I can see maxims and that's about it.
One thing that is interesting, on my phone, I can see links to topics that I am excited for. I can't see it on my computer.
Thanks for all,
Blue Blue

Re: What does this code do? What is purpose of data _null_;? Can we this converted into Proc SQL?

SASKiwi — Sat, 08 May 2021 02:48:38 GMT

I believe @Kurt_Bremser was referring to this documentation link from his earlier post, not the link to his maxims list.

Hint: study the documentation of the %DO Statement.

I suggest you study this thoroughly to understand how macro DO loops work.