Controlling your formats

During my 35 years of using SAS® software, I have found the CNTLIN and CNTLOUT options in the FORMAT procedure to be among the most useful features that I routinely suggest to other SAS users. The CNTLIN option enables you to create user-defined formats from a SAS data set (input control data set). The CNTLOUT option enables you to create a SAS data set (output control data set) containing format details from an entry in a SAS format catalog.

In this blog post, I provide a few examples demonstrating how to use the CNTLIN option. I also mention how to use the CNTLOUT option to store your format information in case you need to move to a new operating environment.

You can store all the format details from a SAS format catalog in a CNTLOUT data set and later restore them in a format catalog in your new operating environment using the CNTLIN option. For details, see SAS Usage Note 22194: “How to use the CNTLOUT= and CNTLIN= options in PROC FORMAT to move formats from one platform to another.”

A data set for the CNTLIN option contains variables that give specific information about ranges and values. At a minimum, the data set must contain the following variables:

FMTNAME specifies a character variable whose value is the format or informat name.
START specifies a variable that gives the range's starting value.
LABEL specifies a variable whose value is associated with a format or an informat.

For details about input and output control data sets, see the “FORMAT Procedure” section of Base SAS® 9.4 Procedures Guide, Seventh Edition.

Create a Numeric Format

The following simple example using the CNTLIN option creates a numeric format named respf:

 data test;                                         
    input response desc $20.;                       
 datalines;                                         
 1  Strongly Disagree                               
 2  Disagree                                        
 3  Neutral                                         
 4  Agree                                           
 5  Stongly Agree                                   
 ;                                                  
 run;                                               
 
 data crfmt;                                        
    set test;                                       
    start=response;                                 
    label=desc;                                     
    fmtname='respf';                                
 run;                                               
 
 proc format library=work cntlin=crfmt fmtlib;      
    select respf;                                   
 run;

Controlling Your Formats

Reveal Data Set Variables

To see the other variables that are included in data sets created by the CNTLIN and CNTLOUT options, use CNTLOUT to create a data set for the respf format created above:

 proc format library=work cntlout=outfmt;       
    select respf;                               
 run;                                      
 proc print data=outfmt;                        
 run;

Add Additional Ranges

To add another range to the respf format, you can use DATA step processing with the data set created by the CNTLOUT option. Then, re-create the format using the CNTLIN option:

data infmt;                                               
    set outfmt end=last;                                   
    output;                                                
    if last then do;                                       
       HLO='O';  /* indicates a special other range  */      
       label='NA';                                         
       output;                                             
    end;                                                   
 run;                                                     
 
 proc format library=work cntlin=infmt fmtlib;             
    select respf;                                          
 run;

Convert a State Name to Its Postal Abbreviation

One use for the CNTLIN option is to create a format that converts a state name to its 2-letter postal abbreviation. For example, this option can convert 'North Carolina' to 'NC'. Because SAS does not have a function or format to convert state names to postal abbreviations, this is an excellent use of the CNTLIN option.

We can use data from the SASHELP.ZIPCODE data set to create a user-defined format using the CNTLIN option, as shown below:

proc sql noprint;                               
    create table crfmt as                        
    select distinct statename as start,          
           statecode as label,                   
           '$mystate' as fmtname                 
    from sashelp.zipcode;                        
 quit;                                           
 
 proc format library=work cntlin=crfmt fmtlib;   
    select $mystate;                             
 run;

Identify State Capitals

In a similar manner, we can use the MAPS.USCITY data set to create a user-defined format that identifies state capitals from the 2-letter state abbreviation. See the sample code and partial results below:

proc sql noprint;                                 
   create table crfmt as                          
   select distinct statecode as start,            
          city as label,                          
          '$mycity' as fmtname                    
   from maps.uscity                               
   where capital='Y';                             
 quit;                                            
 
proc format library=work cntlin=crfmt fmtlib;     
   select $mycity;                                
run;

Use External Data Sources

You can gather information from external data sources and read that information into a data set created by the CNTLIN option to create user-defined formats.

The following example uses ICD10 medical diagnosis codes. I downloaded a list of ICD10 codes and their descriptions into a Microsoft Excel file from the Center for Medicare & Medicaid Services website. Then, I created a user-defined format from the first 25 records:
Note: You can also download the codes as a text file.

/* This code reads in the Excel file.   */                                                                  
proc import out==myicd10                                              
   datafile= "C:\Section111ValidICD10-2017.xlsx"   
   dbms=excelcs replace;                                                
   range="'Valid ICD10 2017 &amp; NF Exclude$'";                            
   scantext=yes;                                                        
   usedate=yes;                                                         
   scantime=yes;                                                        
run;                                                                    
 
 
data crfmt;                                         
   set myicd10 (obs=25);                         
   fmtname='$myicd';                                
   start=code;                                      
   label=short_description;                         
run;  
 
title1 'ICD10 Format';                                                      
title3 'FMTLIB results only display the first 40 characters of the label';  
proc format library=work cntlin=crfmt fmtlib;       
   select $myicd;                                   
run;

A more complicated example that uses other data set variables created by the CNTLIN option is included in the linked sample program in Sample 47312: “Create a user-defined format containing decile ranges from PROC UNIVARIATE results.”

If you can think of a scenario in which the CNTLIN format would be helpful, give it a try. If you have questions, you can ask via SAS Communities or contact us in SAS Technical Support.

1 Comment

Peter Lancashire on December 11, 2017 7:38 am

What is the efficiency of very long format lists? I would use SQL joins for all of the examples you give here. They have the advantage of a clean well-known syntax and indexes. A view would (should) save the intermediate table.
.
In case anyone at SAS would like to use a non-USA example for all us customers out here in the sticks, you could try the départements in France. There are others. 🙂

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