Count itab rows that meet some condition?

Question

I get a internal table from a Function Module call that returns ~ 100 rows. About 40% of the rows are not relevant to me because I only need the entries with PAR1 = "XYZ". On SQL tables (transparent tables), I can use a

select count(*) from tab where PAR1 = "XYZ" 

to get the number of valid entries.

Looking at the documentation, all I could find was the READ Table syntax to iterate through the table. My current approach is to basically have a loop and increase if the row contains the value I want. But this seems very inefficient.

Is there a better approach for my requirement?

Answer 1

As from 740 SP05 you can use:

DATA(lv_lines) = REDUCE i( INIT x = 0 FOR wa IN gt_itab
                    WHERE( F1 = 'XYZ' ) NEXT x = x + 1 ).

for counting the number of lines in gt_itab meeting codntion f1 = 'xyz'.

Answer 2

Do whatever feels right to you. With ~100 rows, virtually nothing will make a huge difference in runtime. For me, stability would be more important than speed in this case.

That being said, you could try this:

LOOP AT lt_my_table TRANSPORTING NO FIELDS WHERE par1 = 'XYZ'.
  ADD 1 TO l_my_counter.
ENDLOOP.

Answer 3

If the entries in the internal table are irrelevant you could do something like this.

DELETE lt_table WHERE par1 <> 'XYZ'.

Then you can count the remaining relevant records by using lines( lt_table ) or DESCRIBE TABLE lt_table LINES l_number_of_lines.

Here is an example.

TYPES: BEGIN OF tt_test,
  par1 TYPE c LENGTH 3,
  END OF tt_test.

DATA: lt_table TYPE TABLE OF tt_test.
DATA: l_number_of_lines TYPE i.
FIELD-SYMBOLS: <fs_par1> LIKE LINE OF lt_table.

APPEND INITIAL LINE TO lt_table ASSIGNING <fs_par1>.
<fs_par1>-par1 = 'XYZ'.
APPEND INITIAL LINE TO lt_table ASSIGNING <fs_par1>.
<fs_par1>-par1 = 'ABC'.
APPEND INITIAL LINE TO lt_table ASSIGNING <fs_par1>.
<fs_par1>-par1 = 'XYY'.
APPEND INITIAL LINE TO lt_table ASSIGNING <fs_par1>.
<fs_par1>-par1 = 'XYZ'.
APPEND INITIAL LINE TO lt_table ASSIGNING <fs_par1>.
<fs_par1>-par1 = 'XYZ'.

l_number_of_lines = LINES( lt_table ).
WRITE / l_number_of_lines.
DESCRIBE TABLE lt_table LINES l_number_of_lines.
WRITE / l_number_of_lines.
DELETE lt_table WHERE par1 <> 'XYZ'.
l_number_of_lines = LINES( lt_table ).
WRITE / l_number_of_lines.