topic Re: Hash sort in SAS Programming

Hash sort

mariopellegrini — Mon, 04 Apr 2016 07:33:06 GMT

I’d like to sort a dataset tab1 by ch, but I do not get the expected result:

data tab1;

input ch:$30. val1:8.;

datalines;

D 9

B 1

A 6

C 7

run;

data tab1_sort;

if 0 then set tab1;

declare hash sortha(dataset: 'tab1', ordered='d', multidata='y');

declare hiter iter('sortha');

rc=sortha.definekey ("ch" );

rc=sortha.defineData("ch", "val1");

rc=sortha.definedone();

do while ( rc = 0 );

rc = iter.prev(); if rc=0 then output tab1_sort;

end;

run;

I’d like to obtain the same result from the following proc sort:

proc sort data=tab1 out=tab1_sort;

by ch;

run;

Re: Hash sort

Kurt_Bremser — Mon, 04 Apr 2016 07:40:21 GMT

Look at your log. You get WARNINGs in the declare hash statement.

Edit: replace the equal signs with colons.

Re: Hash sort

RW9 — Mon, 04 Apr 2016 08:17:10 GMT

Erm, why not use the proc sort then, that is what its for and any code you write will be slower/less resource friendly?

Re: Hash sort

Haikuo — Mon, 04 Apr 2016 13:22:24 GMT

Also, in your Hash code, you specified ordered='d'; however, I couldn't find the equivalent settings in your Proc Sort, as the default is 'ascend'.

Re: Hash sort

data_null__ — Mon, 04 Apr 2016 14:02:55 GMT

@Haikuo Using a HASH to sort it appears that ordering is applied to all keys and cannot duplicate PROC SORT exactly where any KEY may have a different descending/ascending option. Do you know if each key variable's order can be specified using HASH.

Re: Hash sort

data_null__ — Mon, 04 Apr 2016 14:09:34 GMT

Would OUTPUT method be easier.

data tab1;
   input ch:$30. val1:8.;
   datalines;
D 9
D 8
B 1
A 6
C 7
;;;;
   run;
 
data _null_;
   if 0 then set tab1;
   declare hash sortha(dataset: 'tab1', ordered:'d', multidata&colon;'y');
   sortha.definekey ("ch" );
   sortha.defineData(all:'yes');
   sortha.definedone();
   sortha.output(dataset:'tab1_sort');
   stop;
   run;
proc sort data=tab1 out=tab2_sort;
   by descending ch;
   run;
proc compare base=tab1_sort compre=tab2_sort listequalvars;
   run;

Re: Hash sort

Haikuo — Mon, 04 Apr 2016 14:15:01 GMT

@data_null__, I am not aware of such an implemenation of Hash object in SAS 9.4. So you are correct, the option will apply to ALL keys.

Haikuo