ABAP Keyword Documentation → ABAP − Reference → Processing Internal Data → Internal Tables → Expressions and Functions for Internal Tables
FOR - Table Iterations
Other versions:
7.31 | 7.40 | 7.54
Syntax Forms
Read rows of internal tables
1. ... FOR wa|<fs> IN itab [INDEX INTO idx] [
cond] [let_exp] ...
Group rows of internal tables
2. ... FOR GROUPS [group|<group>] OF wa|<fs> IN itab
[INDEX INTO idx] [cond]
GROUP BY group_key
[ASCENDING|DESCENDING [AS TEXT]]
[WITHOUT MEMBERS]
[let_exp] ...
Read group members of internal tables
3. ... FOR { wa|<fs> IN GROUP group [INDEX INTO idx] [
WHERE ( log_exp )] }
| { GROUPS OF
wa|<fs> IN GROUP group [INDEX INTO idx] [
WHERE ( log_exp )]
GROUP BY group_key
[ASCENDING|DESCENDING [AS TEXT]]
[WITHOUT MEMBERS] } [
let_exp] ...
Effect
These syntax forms of an
iteration expression using FOR perform
table iterations.
- When used in a constructor expression with the reduction operator
REDUCE, these forms are known as table reductions.
- When used in a constructor expression with the instance operator
NEWor with the value operatorVALUEfor internal tables, these forms are known as table comprehensions.
A FOR expression like this evaluates the content of an internal table and
its result can be used to construct the result of the wrapper constructor expression. The three variants
of a FOR expression for internal tables work in the same way as the following
variants of the statement LOOP AT itab:
- The first variant
FOR ... IN itabworks in the same way as the regular row variantLOOP AT itabwithout the additionGROUP BY.
- The second variant FOR GROUPS ...
OF works in the same way as the variant for grouping rows with the addition
GROUP BY.
- The third variant
FOR ... IN GROUPworks in the same way as the variantLOOP AT GROUPfor member loops.
The variables or field symbols declared in the FOR expressions are local
in these expressions. The local data from all outer FOR expressions can be
used when their values are defined. As an option, LET expressions
let_exp can be used to define local helper fields at the end of each FOR expression.
The system field sy-tabix is not set by a FOR expression. The addition INDEX INTO can be used instead.
Note
Multiple sequential FOR expressions with different variants (including the
conditional iteration) can be specified in a constructor expression. These expressions then work in the same way as nested loops.
Example
Generates an internal table jtab from an internal table itab using a
table comprehension. Generates a text string str from the internal table jtab using a
table reduction. The result in str is the character string 1, 9, 25.
TYPES itab TYPE TABLE OF i WITH EMPTY KEY.
DATA(itab) = VALUE itab( ( 1 ) ( 3 ) ( 5 ) ).
DATA(jtab) = VALUE itab( FOR wa IN itab ( ipow( base = wa exp = 2 ) ) ).
DATA(str) = REDUCE string( INIT s = ``
FOR wa IN jtab
NEXT s = COND #( WHEN s = `` THEN |{ wa }|
ELSE |{ s }, { wa }| ) ).