How to change the Missing value display format?
Options Missing ='*';
When you check for ordinary missing numeric values, you can use code that is similar to the following:
if numvar=. then do;
If your data contains special missing values, you can check for either an ordinary or special missing value with a statement that is similar to the following:
if numvar<=.z then do;
To check for a missing character value, you can use a statement that is similar to the following:
if charvar=' ' then do;
The MISSING function enables you to check for either a character or numeric missing value, as in:
if missing(var) then do;
In each case, SAS checks whether the value of the variable in the current observation satisfies the condition specified. If it does, SAS executes the DO group.
values have a value of
Special Missing Values
The result of any numeric missing value in a SAS expression is a period. Thus, both special missing values and ordinary numeric missing values propagate as a period.
Preventing Propagation of Missing Values (special missing)
put a= b= c=;