In this post, you will learn
- For Loop for Internal Tables
- Keyword LET
- Nested For Loops
Visit ABAP 7.4+ Syntaxes / ABAP Expressions to read all the posts from the series ABAP 7.4 and beyond.
FOR Iteration for Single Table
FOR is also called Iteration Expression.
Consider below code
This is a simple For Loop for table lt_flights. Index keyword is optional here. This code simply transfers data from one table to another.
This is another way to write LOOP AT and APPEND kind of code.
Similar to LOOP AT, you can also write where conditions except the mandatory ( ).
FOR Iteration and LET expression
LET can be used to define variables and assign them to target table fields.
Nested FOR Iterations
This is similar to LOOP inside a LOOP. This way multiple FOR Iterations can be nested.
Code in text format
TYPES : BEGIN OF ty_flight, seq_num type i, carrier TYPE s_carrname, connect TYPE s_conn_id, fldate TYPE s_date, END OF ty_flight. DATA lt_new_flights TYPE STANDARD TABLE OF ty_flight. SELECT * FROM sflight INTO TABLE @DATA(lt_flights). IF sy-subrc EQ 0. SELECT * FROM scarr INTO TABLE @DATA(lt_scarr). ENDIF. "FOR Iteration lt_new_flights = VALUE #( FOR ls_flight IN lt_flights INDEX INTO lv_index WHERE ( carrid = 'AA' AND connid = '0017' ) LET lv_carrname = lt_scarr[ carrid = ls_flight-carrid ]-carrname IN carrier = lv_carrname ( seq_num = lv_index connect = ls_flight-connid fldate = ls_flight-fldate ) ). cl_demo_output=>display( lt_new_flights ).
"LOOP AT Method DATA: ls_new_flight TYPE ty_flight. LOOP AT lt_flights INTO DATA(ls_flight). ls_new_flight-seq_num = sy-tabix. ls_new_flight-carrier = lt_scarr[ carrid = ls_flight-carrid ]-carrname. ls_new_flight-connect = ls_flight-connid. ls_new_flight-fldate = ls_flight-fldate. APPEND ls_new_flight TO lt_new_flights. ENDLOOP. cl_demo_output=>display( lt_new_flights ).
"Nested FOR Iterations lt_new_flights = VALUE #( FOR ls_scarr in lt_scarr FOR ls_flight IN lt_flights WHERE ( carrid = ls_scarr-carrid ) ( carrier = ls_scarr-carrname connect = ls_flight-connid fldate = ls_flight-fldate ) ).
Read about more such ABAP expressions and exciting new syntaxes: ABAP Expressions (7.4+)
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Hi. That’s a nice article! Have you tried nested loop for records from one internal table which are not in the other. I tried with where condition but it doesn’t work correct. Any idea how to achieve that ?