topic Re: LOOP AT dynamic field in Application Development and Automation Discussions

LOOP AT dynamic field

former_member267246 — Fri, 22 Jun 2007 09:12:46 GMT

I have an internal table that has a structure something like:


BEGIN OF itab,
  item(10) TYPE c,
  opt1 TYPE c,
  opt2 TYPE c,
  opt3 TYPE c,
END OF itab.

It contains values like:

Item   Opt1 Opt2 Opt3
Item1   X
Item2   X    X
Item3             X

I want to create a method that will loop dynamically on the table for a selected field.

Something like

LOOP AT itab WHERE (field) EQ 'X'.

Where "field" could be Opt1, Opt2 or Opt3.

Is this possible? I have tried using a field symbol

ASSIGN (field) TO <fs_field>.
LOOP AT itab WHERE <fs_field> EQ 'X'.

And I get the error "no component exists with the name <fs_field>.

Re: LOOP AT dynamic field

former_member378318 — Fri, 22 Jun 2007 10:03:47 GMT

Hi,

The help says this is not possible:

WHERE log_exp

Effect

WHERE can be specified with all table-types. After WHERE, you can specify any logical expression log_exp in which the first operand of any singular comparison is a component of the internal table. For this reason, all logical expressions are possible except for IS ASSIGNED, IS REQUESTED and IS SUPPLIED. <b>Dynamic specification of a component through bracketed character-type data objects is not possible</b>. Loops at sorted tables must have compatible operands of the logical expression. All rows are read for which the logical expression is true.

Not much help I know but atleast you know where you stand.

Re: LOOP AT dynamic field

former_member378318 — Fri, 22 Jun 2007 10:08:10 GMT

As an alternative perhaps you can move your dynamic check to within the loop?

LOOP AT itab.

ASSIGN (field) TO <fs_field>.

IF <fs_field> EQ 'X'.

...

ENDIF.

ENDLOOP.

Re: LOOP AT dynamic field

Former Member — Fri, 22 Jun 2007 10:18:42 GMT

It can't create a dynamic WHERE condition for the LOOP statament, it's possible for the SELECT only, so u need to check your fields inside of LOOP using field-symbols:

LOOP AT itab.

 IF ........ood ide
    FIELD = <...>.
 ENDIF.

 ASSIGN (FIELD) TO <FS_FIELD>.
 CHECK <FS_FIELD> = 'X'.

ENDLOOP.

The problem can be on the performance because you need to loop all records of the internal table, if you use a WHERE clauses the performace will be better.

So if the ITAB can have many records you should decide if it can be a good idea to use the field-symbols.

Max

Re: LOOP AT dynamic field

former_member267246 — Fri, 22 Jun 2007 10:20:05 GMT

Yes. That's what I'm going to have to go with.

Not the best performance, but it works.