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ABAP Keyword Documentation →  ABAP - Reference →  Program Flow Logic →  Control Structures →  Loops 

WHILE

Short Reference

Other versions: 7.31 | 7.40 | 7.54

Syntax


WHILE log_exp 
  [statement_block] 
ENDWHILE.

Effect

Conditional loop. The statements WHILE and ENDWHILE define a control structure that can contain a closed statement block statement_block. After WHILE, any logical expression log_exp can follow.

The statement block is repeated as long as the logical expression is true, or until it is exited with one of the statements to leave loops. In particular, the statement EXIT is ideal for exiting a loop completely. Within the statement block, the system field sy-index contains the number of previous loop passes, including the current pass. In nested loops, sy-index always refers to the current loop.


Notes

  • The profile parameter rdisp/max_wprun_time limits the maximum execution time of an ABAP program. If this runtime is exceeded because the logical expression is never false and the loop is not exited in any other way, the program is ended by the runtime environment.
  • If WHILE loops are used to construct values or fill internal tables, they can probably be expressed more elegantly using conditional iterations with FOR in constructor expressions.
  • The obsolete addition VARY can be used to process a sequence of data objects in the memory.


Example

Replaces all blanks with hyphens in a character-like data object text. Instead of the loop shown here for demonstration purposes, in a production program the addition ALL OCCURRENCES of the statement REPLACE or the predefined function replace with the value 0 for the argument occ should be used for this task.

DATA text TYPE string VALUE `One Two Three`. 

WHILE sy-subrc = 0. 
  REPLACE ` ` IN text WITH `-`. 
ENDWHILE.

Continue

ENDWHILE