how to remove string?

[Richard]

CREATE USER VARIABLES

MY PROGRAM: edit the objects in the lists
DAT1;
DAT2;

EXPORT PREGUNTA(Y,D)
BEGIN

PRINT;
DAT1:=EXPR("YEAR_"+Y+"_DAY_"+D); // LIST
DAT2:=EVAL("'YEAR_"+Y+"_DAY_"+D+"'"); // NAME LIST

PRINT(DAT2)+PRINT(DAT1);
wait(3);

EDITLIST(DAT1);

END;

example










why the changes made in the list YEAR_1999_DAY_2 are not kept?