SAS Meta Data Driven Programming SAS 9.3

[lmcglone]

Hi,

I am pretty good at programming in SAS but I have been unable to determine a straight forward way to create new variables in a dataset using metadata. I am creating a process that creates datasets using a data dictionary but I would like to incorporate this dictionary for new variables as well. 

Is there a way to create a data dictionary for variables that I want created during data processing that would be based off the variables in the data dictionary? I don't want to include a bunch of if/then statements. As I think about this I believe it may be possible to put if/then statements into a metadata table and run them from a sas macro but I wonder if there is a cleaner way to accomplish that.

let me know if I need to be clearer.

thanks.

[Amir]

Please provide a simple example of data set before and after your change using datalines code, that can be run by anyone as is, explaining what the logic / rules are for creating the new variable(s).

Amir.

[lmcglone]

Hi,

Thanks for the response. Below is a brief program for what I am trying to do.

data dict;
input var $ type $ length 2. varnum 2.;
datalines;
name char 10 1
dept char 10 2
age num 2 3
sex char 1 4
graduated char 1 5
;

data have;
input var1 $ var2 $ var3 2. var4 $ var5 $;
datalines;
John Sales 30 M Y
Mary Acctng 40 F N
;

%macro format;
proc sql noprint;
select var, type, length, varnum
into :mvar1- , :mtype1-, :mlength1-, :mvarnum1-
from dict;
%let count = &sqlobs;
quit;

data temp;
set have;

%do v = 1 %to &count;
rename var&v = &&&mvar&v;
%end; /* end generate variable type conversion */

run;

data want;
set temp;
if graduate = "Y" then school = "college";
run;
%mend;
%format;

I idea is that I have a data dictionary that includes metadata for the variables represented in a dataset. I use this data dictionary to manipulate the dataset (eg. rename variables, change data types, set variable lengths, etc.). In the example I added the if/then statement (if graduate = "Y" then school = "college") creating a new variable named "school". What I want to do is have this variable created from a data dictionary in the macro instead of me adding an if/then statement to create it. I have tried to add the if/then statement to the data dictionary and that works but I wonder if there is a cleaner way to do it. 

The endgame for this idea is to have a data dictionary that I can add variables to the will get added to the dataset whenever the macro runs instead of adding if/then statements.

Hope that helps. Thanks.

[Amir]

I was unable to get the example code provided to complete successfully.

If you need to conditionally assign each new variable you create then you could try creating a separate data set that holds your logic, e.g.:

data logic;
   infile datalines truncover;
   input logic $char200.;
   datalines;
if graduate = "Y" then school = "college"
;

Then any number of logic lines could be used for any number of new variables.

Regards,

Amir.

[ballardw]

If your requirement is for single variables then perhaps an INFORMAT is appropriate to read data in a custom manner.