LOOP
LOOP ( <table_parameter> , <alias_parameter> ).
LOOP ( <table_parameter> , <alias_parameter> , <command interface> ).
LOOP...ENDLOOP is more suitable than DO...ENDDO for looping over table parameters. The normal use case is where some action is to be performed on only a few table lines depending on the content of the table fields. Using LOOP avoids the complex expressions typical for DO…ENDDO.
The command interface allows you to specify WHERE conditions. Only the rows of the table that satisfy the conditions are looped over. If you do not specify conditions in the command interface, or there is no command interface, all the rows of the table are looped over.
The alias parameter must have the same structure as the line type of the table parameter. Select the Alias Parameter checkbox in the parameter list.
Inside the loop, the alias parameter references the current row of the table. If any changes are made to the parameter (for example, assignment of a value to a field), these changes instantly affect the table parameter.
Nesting
LOOP...ENDLOOP loops can be nested. An application for this would be where a field of the row is also a table.
Special Variables
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<C |
Loop table counter - the number of rows looped over. This increments by 1 for each row. |
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&TABIX |
Table index - the index of the current table row. |
Command Interface
The command interface contains a SELECTION field where you can define a table of WHERE conditions.
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FIELD |
Only elementary fields of the row can be used (not structured fields). |
|
VALUE |
If you enter a value, the WHERE condition is equals. If you enter no value, this is ignored (unless you specify something in RANGES). |
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RANGES |
You can specify more complex conditions (for example, SIGN 'I', OPTION 'BT', LOW 'AA', HIGH 'LH'). |
Example
Examples of LOOP...ENDLOOP and DO...ENDDO with the same function:
LOOP ( SPFLI_TABLE , SPFLI_ROW ).
LOG ( SPFLI_ROW-CARRID ).
ENDLOOP.
GETLEN ( SPFLI_TABLE , LEN ).
DO ( LEN ).
LOG ( SPFLI_TABLE[&LPC]-CARRID ).
ENDDO.