Flash / Flex / ActionScript/Language/Comparison Operators
Версия от 09:19, 26 мая 2010; (обсуждение)
Содержание
- 1 Checking Equality or Comparing Values
- 2 Comparison Operators in Actionscript
- 3 Equality (==)
- 4 Greater Than (>) and Less Than (
- 5 Not Equal To (!=)
- 6 Number Comparison
- 7 Strict equality
- 8 The logical inequality operator (!=) returns false if two values are equal and true if they aren"t.
- 9 Two composite items are equal only if they both refer to the identical object
- 10 Use the <= and >= operators to check if one value is less than or equal to, or greater than or equal to, another value:
- 11 Use the < and > operators to check if one value is less than or greater than another value:
- 12 When comparing primitive datatypes, ActionScript compares them by value.
- 13 When you compare composite datatypes, ActionScript compares them by reference.
Checking Equality or Comparing Values
package{
import flash.display.Sprite;
public class Main extends Sprite{
public function Main(){
trace(5 == 6); // Displays: false
trace(6 == 6); // Displays: true
}
}
}
Comparison Operators in Actionscript
Operator Name
== Equals
!= Not equals
> Greater than
< Less than
>= Greater than or equal
<= Less than or equal
Equality (==)
package{
import flash.display.Sprite;
public class Main extends Sprite{
public function Main(){
var weather:String = "rain";
if (weather == "rain") {
trace("bringUmbrella");
}
}
}
}
Greater Than (>) and Less Than (
package{
import flash.display.Sprite;
public class Main extends Sprite{
public function Main(){
var x:int = 0;
var a:int = -1;
var b:int = 0;
var c:int = 1;
trace(x <= a); // Displays: false
trace(x >= a); // Displays: true
trace(x <= b); // Displays: true
trace(x >= b); // Displays: true
trace(x <= c); // Displays: true
trace(x >= c); // Displays: false
}
}
}
Not Equal To (!=)
package{
import flash.display.Sprite;
public class Main extends Sprite{
public function Main(){
var weather:String = "rain";
if (weather != "sun") { trace("bringUmbrella"); }
if (!(weather == "sun")) { trace("bringUmbrella"); }
}
}
}
Number Comparison
Expression Result
6 == 6 true
6 != 6 false
6 > 6 false
6 < 6 false
6 >= 6 true
6 <= 6 true
Strict equality
!== Strict inequality
package{
import flash.display.Sprite;
public class Main extends Sprite{
public function Main(){
var myVariable:Number = 999;
if (myVariable == 4){
trace("if condition true");
}
trace(myVariable);
}
}
}
The logical inequality operator (!=) returns false if two values are equal and true if they aren"t.
package{
import flash.display.Sprite;
public class Main extends Sprite{
public function Main(){
trace(5 != 6); // Displays: true
trace(6 != 6); // Displays: false
}
}
}
Two composite items are equal only if they both refer to the identical object
package{
import flash.display.Sprite;
public class Main extends Sprite{
public function Main(){
var arrayOne:Array = new Array("a", "b", "c");
var arrayTwo:Array = arrayOne;
trace(arrayOne == arrayTwo); // Displays: true
}
}
}
Use the <= and >= operators to check if one value is less than or equal to, or greater than or equal to, another value:
package{
import flash.display.Sprite;
public class Main extends Sprite{
public function Main(){
trace(5 <= 6); // Displays: true
trace(5 >= 5); // Displays: true
}
}
}
Use the < and > operators to check if one value is less than or greater than another value:
package{
import flash.display.Sprite;
public class Main extends Sprite{
public function Main(){
trace(5 < 6); // Displays: true
trace(5 > 5); // Displays: false
}
}
}
When comparing primitive datatypes, ActionScript compares them by value.
package{
import flash.display.Sprite;
public class Main extends Sprite{
public function Main(){
var quantity:Number = 6;
var total:Number = 6;
trace (quantity == total); // Displays: true
}
}
}
When you compare composite datatypes, ActionScript compares them by reference.
package{
import flash.display.Sprite;
public class Main extends Sprite{
public function Main(){
var arrayOne:Array = new Array("a", "b", "c");
var arrayTwo:Array = new Array("a", "b", "c");
trace(arrayOne == arrayTwo); // Displays: false
}
}
}