== Exactly equal

 


 ==
 Exactly equal--binary                           (Relational)
------------------------------------------------------------------------------
 Syntax

     <exp1> == <exp2>

 Type

     All

 Operands

     <exp1> and <exp2> are expressions of the same data type to be
     compared.

 Description

     The exactly equal operator (==) is a binary operator that compares two
     values of the same data type for exact equality depending on the data
     type.  It returns true (.T.) if <exp1> is equal to <exp2> according to
     the following rules:

     .  Array:  Compares for identity.  If <exp1> and <exp2> are
        variable references to the same array, returns true (.T.); otherwise,
        returns
        false (.F.).

     .  Character:  Comparison is based on the underlying ASCII code.
        ASCII codes for alphabetic characters are ascending (e.g., the code
        for "A" is 65 and the code for "Z" is 90).  Unlike the relational
        equality operator (=) , true (.T.) is returned if <exp1> and <exp2>
        are exactly equal including trailing spaces; otherwise, the
        comparison returns false (.F.).  SET EXACT has no effect.

     .  Date:  Dates are compared according to the underlying date
        value; behaves the same as the relational equality operator (=).

     .  Logical:  True (.T.) is exactly equal to true (.T.), and false
        (.F.) is exactly equal to false (.F.).

     .  Memo:  Treated the same as character.

     .  NIL:  True (.T.) if compared to a NIL value; false (.F.) if
        compared to a value of any other data type.

     .  Numeric:  Compared based on magnitude; behaves the same as the
        relational equality operator (=).

     .  Object: Treated the same as array.

 Examples

     .  These examples illustrate how the == operator behaves with
        different data types:

        // Character
        ? "A" == "A"             // Result: .T.
        ? "Z" == "A"             // Result: .F.
        ? "A" == "A "            // Result: .F.
        ? "AA" == "A"            // Result: .F.

        // Array or object

        aOne := { 1, 2, 3 }
        aTwo := { 1, 2, 3 }
        aThree := aOne
        ? aOne == aTwo           // Result: .F.
        // values within the arrays are equal, but the arrays,
        // themselves, are separate and distinct
        ? aOne == aThree         // Result: .T.

See Also: $ < <= <> = (equality) > >=

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