User Guide

!= (inequality) 85
Description
Operator (inequality); tests for the exact opposite of the equality (==) operator. If expression1 is
equal to
expression2, the result is false. As with the equality (==) operator, the definition of
equal depends on the data types being compared, as illustrated in the following list:
• Numbers, strings, and Boolean values are compared by value.
• Objects, arrays, and functions are compared by reference.
• A variable is compared by value or by reference, depending on its type.
Comparison by value means what most people would expect equals to mean—that two
expressions have the same value. For example, the expression (2 + 3) is equal to the expression
(1 + 4) when compared by value.
Comparison by reference means that two expressions are equal only if they both refer to the same
object, array, or function. Values inside the object, array, or function are not compared.
When comparing by value, if
expression1 and expression2 are different data types,
ActionScript will attempt to convert the data type of
expression2 to match that of
expression1. For more information, see “Automatic data typing” on page 24 and “Operator
precedence and associativity” on page 32.
Example
The following example illustrates the result of the inequality (!=) operator:
trace(5 != 8);// returns true
trace(5 != 5) //returns false
The following example illustrates the use of the inequality (!=) operator in an if statement:
var a:String = "David";
var b:String = "Fool";
if (a != b) {
trace("David is not a fool");
}
The following example illustrates comparison by reference with two functions:
var a:Function = function() {
trace("foo");
};
var b:Function = function() {
trace("foo");
};
a(); // foo
b(); // foo
trace(a!=b); // true
a = b;
a(); // foo
b(); // foo
trace(a!=b); // false
// trace statement output:
foo
foo