SPSS® 12.0 Command Syntax Reference

LOOP—END LOOP 835
time, resulting in cases with I=1, J=3, and K increasing from 1 to 4. Once the second loop
has completed three iterations, control passes back to the first loop, and the entire cycle
is repeated for the next increment of #I.
• Once the first loop completes four iterations, control passes out of the looping structures
to END FILE. END FILE defines the resulting cases as a data file, the input program terminates,
and the LIST command is executed.
• This example does not require a LEAVE command because the iteration variables are
scratch variables. If the iteration variables were I, J, and K, LEAVE would be required because
the variables would be reinitialized after each END CASE command.
Example
* Modifying the loop iteration variable.
INPUT PROGRAM.
PRINT SPACE 2.
LOOP A = 1 TO 3. /*Simple iteration
+ PRINT /’A WITHIN LOOP: ’ A(F1).
+ COMPUTE A = 0.
END LOOP
PRINT /’A AFTER LOOP: ’ A(F1).
NUMERIC #B.
LOOP B = 1 TO 3. /*Iteration + UNTIL
+ PRINT /’B WITHIN LOOP: ’ B(F1).
+ COMPUTE B = 0.
+ COMPUTE #B = #B+1.
END LOOP IF #B = 3.
PRINT /’B AFTER LOOP: ’ B(F1).
NUMERIC #C.
LOOP C = 1 TO 3 IF #C NE 3. /*Iteration + WHILE
+ PRINT /’C WITHIN LOOP: ’ C(F1).
+ COMPUTE C = 0.
+ COMPUTE #C = #C+1.
END LOOP.
PRINT /’C AFTER LOOP: ’ C(F1).
NUMERIC #D.
LOOP D = 1 TO 3. /*Iteration + BREAK
+ PRINT /’D WITHIN LOOP: ’ D(F1).
+ COMPUTE D = 0.
+ COMPUTE #D = #D+1.
+ DO IF #D = 3.
+ BREAK.
+ END IF.
END LOOP.
PRINT /’D AFTER LOOP: ’ D(F1).
LOOP E = 3 TO 1. /*Zero-trip iteration
+ PRINT /’E WITHIN LOOP: ’ E(F1).
+ COMPUTE E = 0.
END LOOP.
PRINT /’E AFTER LOOP: ’ E(F1).
END FILE.
END INPUT PROGRAM.
EXECUTE.