SORT Procedure

Example 3: Maintaining the Relative Order of Observations in Each BY Group

Features:	PROC SORT statement option: : EQUALS \| NOEQUALS
Other features:	PROC PRINT

Details

This example does the following:

sorts the observations by the value of the first variable
maintains the relative order with the EQUALS option
does not maintain the relative order with the NOEQUALS option

Program

data insurance;
   input YearsWorked 1 InsuranceID 3-5;
   datalines;
5 421
5 336
1 209
1 564
3 711
3 343
4 212
4 616
;

proc sort data=insurance out=byyears1 equals;

   by yearsworked;
run;

proc print data=byyears1;

   var yearsworked insuranceid;

   title 'Sort with EQUALS';
run;

proc sort data=insurance out=byyears2 noequals;

   by yearsworked;
run;

proc print data=byyears2;

   var yearsworked insuranceid;

   title 'Sort with NOEQUALS';
run;

Program Description

Create the input data set INSURANCE. INSURANCE contains the number of years worked by all insured employees and their insurance IDs.

data insurance;
   input YearsWorked 1 InsuranceID 3-5;
   datalines;
5 421
5 336
1 209
1 564
3 711
3 343
4 212
4 616
;

Create the output data set BYYEARS1 with the EQUALS option. OUT= creates a new data set for the sorted observations. The EQUALS option maintains the order of the observations relative to each other.

proc sort data=insurance out=byyears1 equals;

Sort by the first variable. The BY statement specifies that the observations should be ordered numerically by the number of years worked.

   by yearsworked;
run;

Print the output data set BYYEARS1. PROC PRINT prints the data set BYYEARS1.

proc print data=byyears1;

Specify the variables to be printed. The VAR statement specifies the variables to be printed and their column order in the output.

   var yearsworked insuranceid;

Specify the title.

   title 'Sort with EQUALS';
run;

Create the output data set BYYEARS2. OUT= creates a new data set for the sorted observations. The NOEQUALS option will not maintain the order of the observations relative to each other.

proc sort data=insurance out=byyears2 noequals;

Sort by the first variable. The BY statement specifies that the observations should be ordered numerically by the number of years worked.

   by yearsworked;
run;

Print the output data set BYYEARS2. PROC PRINT prints the data set BYYEARS2.

proc print data=byyears2;

Specify the variables to be printed. The VAR statement specifies the variables to be printed and their column order in the output.

   var yearsworked insuranceid;

Specify the title.

   title 'Sort with NOEQUALS';
run;

Output

Note that sorting with the EQUALS option versus sorting with the NOEQUALS option causes a different sort order for the observations where YearsWorked=3.