Warren Repole

Don't Be a SAS® Dinosaur: Modernize Your SAS Programs
by Warren Repole

Variable Names: Rename a Numbered Range List

Scenario:

You have a set of variables whose names start with the same "root" characters and end with a number in sequence. You wish to change the "root" part of each name and/or the numeric "suffix" values.

The traditional rename syntax has each individual variable listed with its corresponding new name.

The old way: Macro-Generated Rename List

The original approach is to build a rename list using a macro loop.

Download this program 
%macro renameloop(oldprefix=X,newprefix=Y,
                  oldstart=1,newstart=1,count=1);
  %local i;
  %do i=1 %to &count;
    &oldprefix%eval(&oldstart+&i-1) = &newprefix%eval(&newstart+&i-1)
  %end;
%mend renameloop;
proc sort data=sashelp.pricedata out=pricedata nodupkey;
  by Date;
run;
%let renames=%renameloop(oldprefix=Price,newprefix=UnitPriceProduct,count=17);
options symbolgen;
data Prices2002;
  set pricedata;
  where Date between "01jan2002"d and "30jun2002"d;
  rename &renames ;
run;
options nosymbolgen;
proc print data=Prices2002 heading=h;
  id Date;
  format Date date9.;
  var UnitPrice:;
  title1 "Product Prices throughout First Half of 2002";
run;

SAS Log

495   %macro renameloop(oldprefix=X,newprefix=Y,
496                     oldstart=1,newstart=1,count=1);
497     %local i;
498     %do i=1 %to &count;
499       &oldprefix%eval(&oldstart+&i-1) = &newprefix%eval(&newstart+&i-1)
500     %end;
501   %mend renameloop;
502   proc sort data=sashelp.pricedata out=pricedata nodupkey;
503     by Date;
504   run;
 
NOTE: There were 1020 observations read from the data set SASHELP.PRICEDATA.
NOTE: 960 observations with duplicate key values were deleted.
NOTE: The data set WORK.PRICEDATA has 60 observations and 28 variables.
 
505   %let renames=%renameloop(oldprefix=Price,newprefix=UnitPriceProduct,count=17);
506   options symbolgen;
507   data Prices2002;
508     set pricedata;
509     where Date between "01jan2002"d and "30jun2002"d;
SYMBOLGEN:  Macro variable RENAMES resolves to Price1 = UnitPriceProduct1     Price2 =
            UnitPriceProduct2     Price3 = UnitPriceProduct3     Price4 = UnitPriceProduct4
                Price5 = UnitPriceProduct5     Price6 = UnitPriceProduct6     Price7 =
            UnitPriceProduct7     Price8 = UnitPriceProduct8     Price9 = UnitPriceProduct9
                Price10 = UnitPriceProduct10     Price11 = UnitPriceProduct11     Price12 =
            UnitPriceProduct12     Price13 = UnitPriceProduct13     Price14 =
            UnitPriceProduct14     Price15 = UnitPriceProduct15     Price16 =
            UnitPriceProduct16     Price17 = UnitPriceProduct17
510     rename &renames ;
511   run;
 
NOTE: There were 6 observations read from the data set WORK.PRICEDATA.
      WHERE (Date>='01JAN2002'D and Date<='30JUN2002'D);
NOTE: The data set WORK.PRICES2002 has 6 observations and 28 variables.
 
512   options nosymbolgen;
513   proc print data=Prices2002 heading=h;
514     id Date;
515     format Date date9.;
516     var UnitPrice:;
517     title1 "Product Prices throughout First Half of 2002";
518   run;
 
NOTE: There were 6 observations read from the data set WORK.PRICES2002.

SAS Listing Output

Product Prices throughout First Half of 2002
 
            Unit     Unit     Unit     Unit     Unit     Unit     Unit     Unit     Unit
            Price    Price    Price    Price    Price    Price    Price    Price    Price
     date Product1 Product2 Product3 Product4 Product5 Product6 Product7 Product8 Product9
 
01JAN2002   52.3     115.0    33.4     67.9     36.0     48.60     42       59      65.2
01FEB2002   52.3     115.0    33.4     67.9     36.0     48.60     42       59      65.2
01MAR2002   52.3     103.5    33.4     67.9     28.8     48.60     42       59      65.2
01APR2002   52.3     115.0    33.4     67.9     36.0     48.60     42       59      65.2
01MAY2002   52.3     115.0    33.4     67.9     36.0     48.60     42       59      65.2
01JUN2002   52.3     115.0    33.4     67.9     36.0     43.74     42       59      65.2
 
             Unit      Unit      Unit      Unit      Unit      Unit      Unit      Unit
            Price     Price     Price     Price     Price     Price     Price     Price
     date Product10 Product11 Product12 Product13 Product14 Product15 Product16 Product17
 
01JAN2002   56.90     171.40    147.0     122.0       53      120.20      83       80.5
01FEB2002   51.21     171.40    147.0     122.0       53      120.20      83       80.5
01MAR2002   56.90     171.40    147.0     122.0       53      120.20      83       80.5
01APR2002   56.90     154.26    147.0     122.0       53      108.18      83       80.5
01MAY2002   56.90     171.40    132.3     122.0       53      120.20      83       80.5
01JUN2002   56.90     171.40    147.0     103.7       53      120.20      83       80.5
stego

The new way: Use a Variable List as the Rename List
(available in SAS Version 8)

An alternate approach is to use the numbered range list form of the RENAME= data set option and/or RENAME statement.

Download this program 
proc sort data=sashelp.pricedata out=pricedata nodupkey;
  by Date;
run;
data Prices2002;
  set pricedata;
  where Date between "01jan2002"d and "30jun2002"d;
  rename Price1-Price17 = UnitPriceProduct01-UnitPriceProduct17;
run;
proc print data=Prices2002 heading=h;
  id Date;
  format Date date9.;
  var UnitPrice:;
  title1 "Product Prices throughout First Half of 2002";
run;

SAS Log

530   proc sort data=sashelp.pricedata out=pricedata nodupkey;
531     by Date;
532   run;
 
NOTE: There were 1020 observations read from the data set SASHELP.PRICEDATA.
NOTE: 960 observations with duplicate key values were deleted.
NOTE: The data set WORK.PRICEDATA has 60 observations and 28 variables.
 
533   data Prices2002;
534     set pricedata;
535     where Date between "01jan2002"d and "30jun2002"d;
536     rename Price1-Price17 = UnitPriceProduct01-UnitPriceProduct17;
537   run;
 
NOTE: There were 6 observations read from the data set WORK.PRICEDATA.
      WHERE (Date>='01JAN2002'D and Date<='30JUN2002'D);
NOTE: The data set WORK.PRICES2002 has 6 observations and 28 variables.
 
538   proc print data=Prices2002 heading=h;
539     id Date;
540     format Date date9.;
541     var UnitPrice:;
542     title1 "Product Prices throughout First Half of 2002";
543   run;
 
NOTE: There were 6 observations read from the data set WORK.PRICES2002.

SAS Listing Output

Product Prices throughout First Half of 2002
 
                Unit         Unit         Unit         Unit         Unit         Unit
               Price        Price        Price        Price        Price        Price
     date    Product01    Product02    Product03    Product04    Product05    Product06
 
01JAN2002       52.3        115.0         33.4         67.9         36.0        48.60
01FEB2002       52.3        115.0         33.4         67.9         36.0        48.60
01MAR2002       52.3        103.5         33.4         67.9         28.8        48.60
01APR2002       52.3        115.0         33.4         67.9         36.0        48.60
01MAY2002       52.3        115.0         33.4         67.9         36.0        48.60
01JUN2002       52.3        115.0         33.4         67.9         36.0        43.74
 
                Unit         Unit         Unit         Unit         Unit         Unit
               Price        Price        Price        Price        Price        Price
     date    Product07    Product08    Product09    Product10    Product11    Product12
 
01JAN2002        42           59          65.2        56.90        171.40       147.0
01FEB2002        42           59          65.2        51.21        171.40       147.0
01MAR2002        42           59          65.2        56.90        171.40       147.0
01APR2002        42           59          65.2        56.90        154.26       147.0
01MAY2002        42           59          65.2        56.90        171.40       132.3
01JUN2002        42           59          65.2        56.90        171.40       147.0
 
                Unit         Unit         Unit         Unit         Unit
               Price        Price        Price        Price        Price
     date    Product13    Product14    Product15    Product16    Product17
 
01JAN2002      122.0          53         120.20         83          80.5
01FEB2002      122.0          53         120.20         83          80.5
01MAR2002      122.0          53         120.20         83          80.5
01APR2002      122.0          53         108.18         83          80.5
01MAY2002      122.0          53         120.20         83          80.5
01JUN2002      103.7          53         120.20         83          80.5

Advantages of the alternate approach: Good

  • No macro code is involved, especially indirect macro variable references.
  • It is not necessary to list each individual variable within the rename list syntax.
  • Numeric suffixes can be shifted easily.

Disadvantages of the alternate approach: Bad

  • None identified

Additional documentation for this technique can be found in SAS® 9.2 Language Reference: Dictionary. Cary, NC: SAS Institute Inc.

Visit http://support.sas.com/documentation/onlinedoc/sas9doc.html for SAS 9 documentation.

The URL for this page is http://www.repole.com/dinosaur/renamelist.html

These techniques are mentioned in other SAS references and publications:

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