MACROMEDIA FLASH MX, Справочник

Страница: 81 / 1104

== (equality) 81
== (equality)
Availability
Flash Player 5.
Usage
expression1 == expression2
Parameters
expression1,expression2
A number, string, Boolean value, variable, object, array,
or function.
Returns
A Boolean value.
Description
Operator (equality); tests two expressions for equality. The result is
true
if the expressions
are equal.
The definition of equal depends on the data type of the parameter:
•
Numbers and Boolean values are compared by value and are considered equal if they have the
same value.
•
String expressions are equal if they have the same number of characters and the characters
are identical.
•
Variables representing objects, arrays, and functions are compared by reference. Two such
variables are equal if they refer to the same object, array, or function. Two separate arrays are
never considered equal, even if they have the same number of elements.
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” and “Operator precedence and
associativity” in Using ActionScript in Flash .
Example
The following example uses the equality (
==)
operator with an
if
statement:
var a:String = "David", b:String = "David";
if (a == b) {
trace("David is David");
}
The following examples show the results of operations that compare mixed types:
var x:Number = 5;
var y:String = "5";
trace(x == y); // output: true
var x:String = "5";
var y:String = "66";
trace(x == y); // output: false
var x:String = "chris";