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Subsetting data in SAS is the process of extracting a subset of data from a larger dataset. This can be done using a variety of methods, such as the where clause, subsetting if statements, and the data step. Each method has its own advantages, depending on the data and the desired outcome. For example, the where clause is a simple and efficient way to subset data, while subsetting if statements are more flexible and allow for more complex subsetting. The data step is also useful for creating new datasets from the existing data.
Here are the three most common ways to subset a dataset in SAS:
Method 1: Choose Which Columns to Keep
data new_data;
set original_data;
keep var1 var3;
run;
Method 2: Choose Which Columns to Drop
data new_data;
set original_data;
drop var4;
run;
Method 3: Choose Which Rows to Keep Based on Condition
data new_data;
set original_data;
if var1 < 25 then delete;
run;
The following examples show how to use each method with the following dataset in SAS:
/*create dataset*/
data original_data;
input team $ points rebounds;
datalines;
Warriors 25 8
Wizards 18 12
Rockets 22 6
Celtics 24 11
Thunder 27 14
Spurs 33 19
Nets 31 20
;
run;
/*view dataset*/
proc print data=original_data;
Example 1: Choose Which Columns to Keep
The following code shows how to subset a dataset by using the KEEP statement to keep only certain columns:
/*create new dataset*/
data new_data;
set original_data;
keep team points;
run;
/*view new dataset*/
proc print data=new_data;
Example 2: Choose Which Columns to Drop
The following code shows how to subset a dataset by using the DROP statement to drop specific columns:
/*create new dataset*/
data new_data;
set original_data;
drop points;
run;
/*view new dataset*/
proc print data=new_data;
Example 3: Choose Which Rows to Keep Based on Condition
The following code shows how to subset a dataset by using the DELETE statement to drop specific rows from the dataset where the value in the points column is less than 25:
/*create new dataset*/
data new_data;
set original_data;
if points < 25 then delete;
run;
/*view new dataset*/
proc print data=new_data;
You can also use the OR “|” operator to drop the rows where points is less than 25 or rebounds is less than 10:
/*create new dataset*/
data new_data;
set original_data;
if points < 25 | rebounds < 10 then delete;
run;
/*view new dataset*/
proc print data=new_data;
You can also use the AND “&” operator to drop the rows where points is less than 25 and rebounds is less than 10:
/*create new dataset*/
data new_data;
set original_data;
if points < 25 & rebounds < 10 then delete;
run;
/*view new dataset*/
proc print data=new_data;
The following tutorials explain how to perform other common tasks in SAS: