MACROMEDIA FLASH 8-ACTIONSCRIPT 2.0 LANGUAGE, Reference

Page: 185 / 1378

Operators 185
expression2 : Object
- A number, string, Boolean value, variable, object, array, or
function.
Returns
Boolean
- The Boolean result of the comparison.
Example
The comments in the following code show the returned value of operations that use the
equality and strict equality operators:
// Both return true because no conversion is done
var string1:String = "5";
var string2:String = "5";
trace(string1 == string2); // true
trace(string1 === string2); // true
// Automatic data typing in this example converts 5 to "5"
var string1:String = "5";
var num:Number = 5;
trace(string1 == num); // true
trace(string1 === num); // false
// Automatic data typing in this example converts true to "1"
var string1:String = "1";
var bool1:Boolean = true;
trace(string1 == bool1); // true
trace(string1 === bool1); // false
// Automatic data typing in this example converts false to "0"
var string1:String = "0";
var bool2:Boolean = false;
trace(string1 == bool2); // true
trace(string1 === bool2); // false
The following examples show how strict equality treats variables that are references differently
than it treats variables that contain literal values. This is one reason to consistently use String
literals and to avoid the use of the
new
operator with the String class.
// Create a string variable using a literal value
var str:String = "asdf";
// Create a variable that is a reference
var stringRef:String = new String("asdf");
// The equality operator does not distinguish among literals, variables,
// and references
trace(stringRef == "asdf"); // true
trace(stringRef == str); // true
trace("asdf" == str); // true
// The strict equality operator considers variables that are references
// distinct from literals and variables
trace(stringRef === "asdf"); // false
trace(stringRef === str); // false