Scripting Guide - SAS

Chapter 9 Data Tables 251
Messages for Data Tables
:age; //returns .
Why? This default protects you from getting a result that might look reasonable for the whole data table but
is actually based on only one row. It also protects you from accidentally overwriting data values when
making assignments to ambiguous names under most circumstances. (You can have even more complete
protection by using the prefix or infix : operator to refer unambiguously to a data column and the prefix ::
operator to refer unambiguously to a global script variable. See “Stored expressions” on page 183 in the
“Programming Methods” chapter.)
You can use the Row() operator to get or set the current row number. Row( ) is an example of an L-value
expression in JSL: an operator that returns its value unless you place it before an assignment operator (=, +=,
and so on.) to set its value.
Row(); //returns the number of the current row (0 by default)
x=Row(); //stores the current row number in x
Row()=7; //makes the 7th row current
Row()=7; :age; //returns 12
Note that the current row setting only lasts for the portion of a script that you select and submit. After the
script executes, the current row setting resets to the default (row 0, or no row). Therefore, a script submitted
all at once can produce different results from the same script submitted a few lines at a time.
How Many Rows and Columns?
For Each Row
The NRow and NCol operators count the rows and columns in a data table (or matrix; see the “Data
Structures” chapter on page 137).
NRow(dt); // number of rows
NCol(dt); // number of columns
To iterate a script on each row of the current data table, put For Each Row around the script.
For Each Row( if(:age>15, show(age)) );
A typical use is for setting row states without creating a new formula column in the data table. The scripts
below are similar except that the first one creates a row state column and the For Each Row version simply
sets the row state without creating a column.
new column("My Rowstate", rowstate, formula( color state(age-9)) );
for each row(color of(rowstate())=age-9);
To iterate a script on each row meeting a specified condition, combine For Each Row and If.
for each row(marker of(rowstate())=if(sex=="F",2,6));
Break and Continue can be used to control execution of a For Each Row loop. For details about using these
two functions, see “Break and Continue” on page 85 in the “JSL Building Blocks” chapter.