Download SAS work dataset in Viya 4

In Viya 4 SAS Studio, we can not download directly from SAS libraries but export text file (e.g. comma-delimited, tab-delimited). As you can see, we can upload and download files from Contents. Therefore, we can leverage Viya Files service to download SAS datasets. Below is the sample code.

data result;
	set sashelp.class;
run;

filename out filesrvc folderpath='/Users/xxxxx/My Folder' 
	filename='result.sas7bdat' recfm=n lrecl=32767;
filename in "%sysfunc(pathname(work))/a.sas7bdat" recfm=n lrecl=32767;

data _null_;
    rc = fcopy('in', 'out');
    put rc=;
    length msg $1000;
    msg = sysmsg();
    put msg=;
run;

Split long string: VARCHAR + data _null_

As we know, the maximum length for character variable is 32767. To handle the string which is longer than 32767, we can split it, store in dataset and recomine it. Below is the sample code:

filename source "file_with_long_string";
filename target "file_with_new_long_string";

data source;
    infile source recfm=f lrecl=32000 pad;
    input text $char32000.;
run;

data target;
    length x $ 32767;
    set source;
    x = prxchange('s/old/new/', -1, text);
run;

data _null_;
    length y varchar(5000000);

    do until(eof);
        set target end=eof;
        y = cats(y, x);
    end;

    file target lrecl = 5000000;
    put y;
run;

Hash way to split SAS Table

In traditional SAS way, it will leverage SAS macro to split the SAS dataset. If you are bored with that, you may like the hash way below. Enjoy!

proc sort data=sashelp.class out=class;
    by age;
run;

data _null_ ;
    declare hash h (multidata:"Y", 
    				ordered: "a", 
    				dataset:"class(obs=0)") ;
    h.definekey('name') ;
    h.definedata(all:'Y');
    h.definedone() ;

    do i = 1 by 1 until (last.age);
        set class;
        by age;
        h.add();
    end ;

    h.output(dataset: cats("age_", age));
run;

Summary aggregate using Hash

Below are the key statements to understand hash "Maintaining Key Summaries". It is powerful technique when you understand how it works. However, avoid using SUMINC with MULTIDATA/DO_OVER as they are affecting the sum value and I can not find any explanation in SAS doc.

quote:
The summary value of a hash key is initialized to the value of the SUMINC variable whenever the ADD or REPLACE method is used.
The summary value of a hash key is incremented by the value of the SUMINC variable whenever the FIND, CHECK, or REF method is used.
Note that the SUMINC variable can be negative, positive, or zero valued. The variable does not need to be an integer.The SUMINC value for a key is zero by default.
unquote:

data sample;
    do key = 1,2,3;
        value = key*2;
        output; output;
    end;
run;

data _null_ ;
    if _n_ = 1 then do ;
        declare hash h (suminc:"value", dataset:"sample") ;
        h.defineKey("key") ;
        h.defineDone();

        do until (eof) ;
            set sample end=eof ;
            h.check();
        end;
    end ;

    file print ;

    set sample;
    by key;

    if first.key then do ;
        h.sum(sum:Total);
        put key @10 Total;
    end;
run;

How to loop character A-Z in SAS?

To loop characters A-Z elegantly, we can have two ways as follows:

data _null_;
    put "First method:";
    string = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'; * string from A to Z;
    do i=1 to length(string);
        char = substrn(string, i, 1);
        put char=; 
    end;

    put "Second method (using RANK and BYTE):";
    do i=rank('A') to rank('Z');
        char = byte(i);
        put char=;
    end;
run;

If you can find any way better, please let me know.

How to find hidden macro in batch run

By default, it does not give out any information for macro compilation when the macro definition are %include. It is OK for most time. However, it may be helpful when you want to locate the macro when multiple versions exist. With system option MCOMPILENOTE, we can easily address this problem.
Similarly, we can use MEXECNOTE to get more details on macro execution.

Programmatically, we can add version information in macro description. See blow:

%macro test / des = 'Version 1.0';
%mend;

proc catalog;
contents cat=work.sasmacr; /* list macro description */
quit;

Identify trailing string using $revers.

In SAS, it is easy to identify leading string using ":" operator modifier, e.g. "a =: b". However, there was no easy way to identify trailing ones. Traditionally we could use combination of substr/reverse/length/strip functions. Personally I prefer format $revers as it combines the functionality of substr and left-align. Note that the width should be the length of the character variable.

data _null_;
    a = 'abc efg   ';
    if put(a, $revers10.) =: 'gfe' then put "a has trailing string efg";
run;

/*
Output:
a has trailing string efg
*/

Result: