IN Operator

value IN value_set

value	The value to find in the value_set. This is usually a single value, but if the value_set is a DICTIONARY with a multiple-component key, this may also be a ROW.
value_set	A set of values. This may be a set expression, the SET function, or a DICTIONARY.

The IN operator is shorthand for a collection of OR conditions. It is an operator that will search a set to find an inclusion, resulting in a Boolean return. Using IN is much more efficient than the equivalent OR expression.

Example:

ABCset := ['A', 'B', 'C'];
IsABCStatus := Person.Status IN ABCset;
    //This code is directly equivalent to:
    // IsABCStatus := Person.Status = 'A' OR
    //                Person.Status = 'B' OR
    //                Person.Status = 'C';
       
IsABC(STRING1 char) := char IN ABCset;
Trades_ABCstat := Trades(IsABC(rate));
    // Trades_ABCstat is a record set definition of all those
    // trades with a trade status of A, B, or C

//SET function examples
r := {STRING1 Letter};
SomeFile := DATASET([{'A'},{'B'},{'C'},{'D'},{'E'},
                     {'F'},{'G'},{'H'},{'I'},{'J'}],r);
x := SET(SomeFile(Letter > 'C'),Letter);
y := 'A' IN x;  //results in FALSE
z := 'D' IN x;  //results in TRUE

//DICTIONARY examples:
rec := {STRING color,UNSIGNED1 code};
ColorCodes := DATASET([{'Black' ,0 },
                       {'Brown' ,1 },
                       {'Red'   ,2 },
                       {'White' ,3 }], rec);

CodeColorDCT  := DICTIONARY(ColorCodes,{Code => Color});
OUTPUT(6 IN CodeColorDCT);     //false

ColorCodesDCT := DICTIONARY(ColorCodes,{Color,Code});
OUTPUT(ROW({'Red',2},rec) IN ColorCodesDCT);