Fastest way to move from one itab to another?

Question

What is the fastest way to move one internal table to another internal table (assuming two tables of similar structure)?
a) append lines of table1 to table2.
b) loop at table1.
Move: table1-field1 to table2-field1,
table1-field2 to table2-field2.
Append table2.
Endloop.
c) table2[] = table1[].
d) loop at table1.
Move-corresponding table1 to table2.
Endloop.
e) move table1 to table2.
I think it is option a). Is it correct?

Answer 1

Hi,
Yes option a. is fastest : append lines of table1 to table2
In particular, the quickest way to fill a table line by line is to append lines to a standard table, since a standard table cannot have a unique key and therefore appends the lines without having to check the existing lines in the table.
APPEND LINES OF inttab1 TO inttab2.
This statement appends the whole of ITAB1 to ITAB2. ITAB1 can be any type of table, but its line type must be convertible into the line type of ITAB2.
This method of appending lines of one table to another is about 3 to 4 times faster than appending them line by line in a loop. After the APPEND statement, the system field SY-TABIX
contains the index of the last line appended. When you append several lines to a sorted table, you must respect the unique key (if defined), and not violate the sort order. Otherwise, a runtime
error will occur.
Reference : SDN ABAP Book.
thanx.