Groups data according to the values of the class
variables.
Tip:
PROC TIMEPLOT uses the formatted values of the CLASS variables
to form classes. Thus, if a format groups the values, then the procedure
uses those groups.
specifies one or more
variables that the procedure uses to group the data. Variables in
a CLASS statement are called class variables. Class variables can be numeric or character. Class variables
can have continuous values, but they typically have a few discrete
values that define the classifications of the variable. You do not
have to sort the data by class variables.
The values of the class
variables appear in the listing. PROC TIMEPLOT prints and plots one
line each time the combination of values of the class variables changes.
Therefore, the output typically is more meaningful if you sort or
group the data according to values of the class variables.
Details
Using Multiple CLASS Statements
You can use any number
of CLASS statements. If you use more than one CLASS statement, then
PROC TIMEPLOT simply concatenates all variables from all of the CLASS
statements. The following form of the CLASS statement includes three
variables:
CLASS variable-1 variable-2
variable-3;
It has the same effect
as this form:
CLASS variable-1;
CLASS variable-2;
CLASS variable-3;
Using a Symbol Variable
Normally, you use the CLASS statement
with a symbol variable. (See the discussion of plot
requests.)
In this case, the listing of the plot variable contains a column for
each value of the symbol variable. Each row of the plot contains a
point for each value of the symbol variable. The plotting symbol
is the first character of the formatted value of the symbol variable.
If more than one observation within a class has the same value of
a symbol variable, then PROC TIMEPLOT plots and prints only the first
occurrence of that value and writes a warning message to the SAS log.