Working with SAS Data Sets

Update Observations

Suppose you have updated data and want to change some values in the Class data set. For instance, suppose the student named Henry recently had a birthday. You can do the following:

use the EDIT statement to open the Class data set for input and output
read the data
change the appropriate data value
replace the changed data in the data set

The following statements open the Class data set and use the FIND statement to find the observation number that corresponds to Henry. The observation number is stored in the matrix Obs, as shown in Figure 7.15.

proc iml;
edit Class;
find all where(name={'Henry'}) into Obs;
list point Obs;

Figure 7.15: Selected Observation

   OBS Name     Sex       Age    Height    Weight                               
------ -------- --- --------- --------- ---------                               
     5 Henry    M     14.0000   63.5000  102.5000

You can read in the Age variable, increment its value, and use the REPLACE statement to overwrite the value in the Class data set, as follows:

read point Obs var {Age};
Age = Age + 1;
replace point Obs var {Age};
list point Obs;
close Class;

Figure 7.16: New Value

   OBS Name     Sex       Age    Height    Weight                               
------ -------- --- --------- --------- ---------                               
     5 Henry    M     15.0000   63.5000  102.5000

Figure 7.16 shows that the value for Henry’s age has been updated.