topic Re: Writing Data Driven Programs in SAS Procedures

Writing Data Driven Programs

OPHD1 — Fri, 09 Aug 2013 14:03:44 GMT

I am looking to productionalize some code and would like to make the process more data driven and efficient. I am looking for a way to use do loops, or some other procedure, to drive creation of variables, without specifically identifying each level of a variable.

Basically, I want to take this step:

data example_2;

set example;

if practice_type = 'FQHC' then type = 1;

else if practice_type = 'CAH' then type = 2;

else if practice_type = 'RHC' then type = 3;

else if practice_type = 'Independent_Multi_Site' then type = 4;

else if practice_type = 'Independent_Single_Site' then type = 5;

else type = 6;

run;

And turn it into a step that creates a value for type based on unique values of practice_type, without specifying the level of practice_type; since values may change with additional updates. This will also serve as a QC check to make sure the data is being entered in the same manner (Independent_Single_Site is different from Independent_Single). I've tried using do = 1 to 5 and a combination of first.practice_type and last.practice_type and haven't had any luck. Thank you in advance for any suggestions or reference materials.

Here's a practice data set:

data example;

length practice_type $ 25;

input practice practice_type;

datalines;

001 FQHC

002 Independent_Single_Site

003 RHC

004 Independent_Single_Site

005 Independent_Multi_Site

006 Independent_Single_Site

007 CAH

008 RHC

009 Independent_Single_Site

010 Independent_Multi_Site

011 Independent_Multi_Site

012 CAH

013 Independent_Multi_Site

014 Independent_Single_Site

015 Independent_Multi_Site

016 FQHC

017 CAH

018 Independent_Multi_Site

019 Independent_Single

020 Independent_Multi_Site

021 Independent_Single_Site

022 FQHC

023 FQHC

024 FQHC

025 RHC

;

run;

Re: Writing Data Driven Programs

Tom — Fri, 09 Aug 2013 14:18:26 GMT

Not sure what you mean here.

If you just want to assign a number to each unique value of PRACTICE_TYPE then do something like this.

proc sort data=sample;

by practice_type;

run;

data want ;

set

sample;

by practice_type;

type + (first.practice_type) ;

run;

Re: Writing Data Driven Programs

AncaTilea — Fri, 09 Aug 2013 14:21:38 GMT

Hi, how about something like this:

%let practice_type_values = FQHC,CAH,RHC,Independent_Multi_Site,Independent_Single_Site,Independent_Single;

%let num_options = %eval(%sysfunc(countw("&practice_type_values.")));

%put &num_options;

%macro quick();

%do i = 1 %to &num_options.;

if practice_type ="%scan('&practice_type_values.', &i., ',')" then type = &i.;

%end;

output;

%mend quick;

data example_3;

set example;

%quick;

run;

Re: Writing Data Driven Programs

LarryWorley — Fri, 09 Aug 2013 14:49:35 GMT

I would start with creating a lookup data set with the relationship of practice_type and type. Depending upon your requirements you might add effectiveness dates, an effectiveness flag, etc.

Something like this for your data:

practice_type_level type effectiveness_flag

'FQHC' 1 Yes

'CAH' 2 Yes

'RHC' 3 Yes

'Independent_Multi_Site' 4 Yes

'Independent_Single_Site' 5 Yes

'new practice type tbd' 7 No

'Else value' 9 Yes

You can modify this table as needed.

Your dynamic code can read this table, filtering on the value of the effectiveness_flag if needed.

Then you have sevaral options within SAS to do this:

1. Use this dataset to create a format which is then used in datastep with assignment statement to assign a value to the new type variable. This might be the simplest given my interpretation of your requirements.

2. Use the dataset to create macro vaiable 'arrays' which are then fed to a generic macro. This is similar to Anca approach, but allows dynamic changes to made to the control table instead of being hard-coded in that example.

3. Use the dataset to drive a data _null_ step which uses call execute to generate program,

4. Use the dataset to drive a data _null_ step which writes code to a temporary file which is then %included in job.

You can find references to all of those approaches online and in the SAS documentation.

Let me know if you need more details.

Hope this helps.

Larry

Re: Writing Data Driven Programs

OPHD1 — Fri, 09 Aug 2013 16:06:55 GMT

Thank you Tom, for this simple trick to create the flag in shortened code.

Re: Writing Data Driven Programs

OPHD1 — Fri, 09 Aug 2013 16:07:39 GMT

Thank you Anca, this is a very useful macro. I was not familiar with some of this macro functions, so this was very helpful.

Re: Writing Data Driven Programs

OPHD1 — Fri, 09 Aug 2013 16:08:45 GMT

Thank you Larry, you offered helpful approaches -- I will try Approach # 1. Seems like you know about practice data too -- having a look up table with effective information is a great suggestion.

Re: Writing Data Driven Programs

OPHD1 — Fri, 09 Aug 2013 16:10:41 GMT

Thanks All, I'd like to mark this question as answered, but I'm not sure how. My apologies for my newbie status with these discussion boards.

Re: Writing Data Driven Programs

LarryWorley — Fri, 09 Aug 2013 16:58:30 GMT

You see some buttons inside each reply, which let you mark as correct or as helpful