The COMPUTAB procedure is best understood by examining the following features:

• definition of the report layout with ROWS and COLUMNS statements

• input block

• row blocks

• column blocks

PROC COMPUTAB builds a table according to the specifications in the ROWS and COLUMNS statements. Row names and column names define the rows and columns of the table. Options in the ROWS and COLUMNS statements control titles, spacing, and formatting.

The input block places input observations into the appropriate columns of the report. It consists of programming statements used to select observations to be included in the report, to determine the column into which the observation should be placed, and to calculate row and column values that are not in the input data set.

Row blocks and column blocks perform operations on the values of rows and columns of the report after the input block has executed. Row blocks are a block of programming statements labeled ROWxxxxx: that create or modify row values; column blocks are a block of programming statements labeled COLxxxxx: that create or modify column values. Row and column blocks can make multiple passes through the report for final calculations.

For most reports, these features are sufficient. More complicated applications might require knowledge of the program data vector and the COMPUTAB data table. These topics are discussed in the section Details: COMPUTAB Procedure.