Skip to Content
author's profile photo Former Member
Former Member

LOOP

WHAT IS THE FUN OF AT FIRST AND AT LAST STATEMENT? PLZZ TELL

Add a comment
10|10000 characters needed characters exceeded

Assigned Tags

Related questions

1 Answer

  • author's profile photo Former Member
    Former Member
    Posted on Dec 24, 2007 at 12:39 PM

    AT - control break

    Variants:

    1. AT NEW f.

    2. AT END OF f.

    3. AT FIRST.

    4. AT LAST.

    Variant 1

    AT NEW f.

    Variant 2

    AT END OF f.

    Effect

    f is a sub-field of an internal table or extract dataset (EXTRACT) which is being processed with LOOP, i.e. the variants 1 and 2 only make sense within a LOOP.

    Both "AT NEW f." and "AT END OF f. " introduce processing blocks which are concluded by " ENDAT.".

    These processing blocks are processed whenever the contents of a field f or a sub-field defined before f change as a result of processing with LOOP. "AT NEW f." begins a new group of (table) lines with the same contents as the field f while "AT END OF f." concludes such a group.

    Within the AT ... ENDAT processing of internal tables, all argument fields following f are filled with "*".

    Examples

    1. AT for sub-fields of an internal table

    DATA: BEGIN OF COMPANIES OCCURS 20,

    NAME(30),

    PRODUCT(20),

    SALES TYPE I,

    END OF COMPANIES.

    ...

    LOOP AT COMPANIES.

    AT NEW NAME.

    NEW-PAGE.

    WRITE / COMPANIES-NAME.

    ENDAT.

    WRITE: / COMPANIES-PRODUCT, COMPANIES-SALES.

    AT END OF NAME.

    SUM.

    WRITE: / COMPANIES-NAME, COMPANIES-SALES.

    ENDAT.

    ENDLOOP.

    The AT statements refer to the field COMPANIES-NAME.

    Examples

    2. AT for the field of an extract dataset

    DATA: NAME(30),

    SALES TYPE I.

    FIELD-GROUPS: HEADER, INFOS.

    INSERT: NAME INTO HEADER,

    SALES INTO INFOS.

    ...

    LOOP.

    AT NEW NAME.

    NEW-PAGE.

    ENDAT.

    ...

    AT END OF NAME.

    WRITE: / NAME, SUM(SALES).

    ENDAT.

    ENDLOOP.

    Notes

    If the processing you want to perform on an internal table is fairly restricted (i.e. a WHERE addition with the LOOP statement), do not use the AT statements specified in variants 1 to 5, since the interaction of the WHERE addition and the AT statement is currently not defined.

    When you use LOOP with an extract dataset, fields on hex zero are ignored during control level checking with AT NEW or AT END OF . This procedure is the same as the SORT statement. When sorting extracted datasets, this statement always sorts blank fields (i.e. fields on hex zero) regardless of the sequence (ascending or descending) before all fields that contain values.

    Since fields addressed with AT are not set to an initial value when you enter a LOOP, the first new group of (table) lines in AT NEW f may not be processed, if f happens to be set to this value.

    Variant 3

    AT FIRST.

    Variant 4

    AT LAST.

    Effect

    The variants 3 and 4 only make sense within a LOOP.

    The processing block between AT FIRST and ENDAT is executed before the individual lines are processed; the processing block between AT LAST and ENDAT is executed after all the individual lines have been processed.

    In AT FIRST or AT LAST ... ENDAT processing, all argument fields are filled with "*" (internal tables).

    When you are processing extract datasets, a control total SUM(n) can only be processed with AT END OF or AT LAST.

    Example

    DATA: BEGIN OF COMPANIES OCCURS 20,

    NAME(30),

    PRODUCT(20),

    SALES TYPE I,

    END OF COMPANIES.

    ...

    LOOP AT COMPANIES.

    AT FIRST.

    SUM.

    WRITE: 'Sum of all SALES:',

    55 COMPANIES-SALES.

    ENDAT.

    WRITE: / COMPANIES-NAME, COMPANIES-PRODUCT,

    55 COMPANIES-SALES.

    ENDLOOP.

    Add a comment
    10|10000 characters needed characters exceeded

Before answering

You should only submit an answer when you are proposing a solution to the poster's problem. If you want the poster to clarify the question or provide more information, please leave a comment instead, requesting additional details. When answering, please include specifics, such as step-by-step instructions, context for the solution, and links to useful resources. Also, please make sure that you answer complies with our Rules of Engagement.
You must be Logged in to submit an answer.

Up to 10 attachments (including images) can be used with a maximum of 1.0 MB each and 10.5 MB total.