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Internal Tables, Grouping with FOR Using a Method

This example demonstrates the construction of the group key using the assignment of return values.

Other versions: 7.31 | 7.40 | 7.54

Source Code

    DATA out TYPE REF TO if_demo_output.

    out = REDUCE #(
      INIT o = cl_demo_output=>new( )
      FOR GROUPS <group> OF wa IN flights
            GROUP BY ( tz_from = get_time_zone( wa-airpfrom )
                       tz_to   = get_time_zone( wa-airpto )
                       size    = GROUP SIZE index = GROUP INDEX )
      LET members = VALUE spfli_tab(
                      FOR <member> IN GROUP <group> ( <member> ) ) IN
      NEXT o = o->write( name = `Group key`
                         data = <group>
               )->write( members )->line( ) ).

  out->display( ).

Description

This example works in the same way as the corresponding example for LOOP AT ... GROUP BY, but uses the expression FOR GROUPS ... OF for a table reduction with REDUCE instead of the group loop.In both cases, the group key after GROUP BY is constructed in exactly the same way.

The result of the table reduction is a reference to an object of the class CL_DEMO_OUTPUT to which the results of the grouping are written. The group members are written to a local auxiliary table members using a table comprehension with VALUE. This table comprehension could also be used in the example for LOOP AT ... GROUP BY instead of the member loop.