Flash / Flex / ActionScript/Array/length — различия между версиями

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Версия 09:19, 26 мая 2010

Access the last element of theArray: theArray[theArray.length - 1]

 

package{
  import flash.display.Sprite;
  
  public class Main extends Sprite{
    public function Main(){

        var cities:Array = ["Toronto", "Montreal", "Vancouver", "Waterloo"];
        
        trace(cities); // Toronto,Montreal,Vancouver,Waterloo
    }
  }
}



Determining the Size of an Array

 

package{
  import flash.display.Sprite;
  
  public class Main extends Sprite{
    public function Main(){

        var list:Array = [34, 45, 57];
        trace(list.length);               // Displays: 3
        
        var words:Array = ["this", "that", "the other"];
        trace(words.length);              // Displays: 3
        
        var cards:Array = new Array(24);  
        trace(cards.length);              // Displays: 24
    }
  }
}



Putting an element at index Array .length creates a new element right after the current last element

 
package{
  import flash.display.Sprite;
  
  public class Main extends Sprite{
    public function Main(){
        var array:Array = new Array();
        
        array.push("val 1", "val 2");
        
        array[array.length] = "val 3";
        
        trace(array);
    }
  }
}



Removing Elements with the length Variable

 
To delete elements from the end of the array: set the array"s length variable to a number smaller than the current length:

package{
  import flash.display.Sprite;
  
  public class Main extends Sprite{
    public function Main(){

        var toppings:Array = ["p", "t", "c", "g", "b"];
        toppings.length = 3;
        trace(toppings);  //p,t,c
    }
  }
}



The length property of an array returns the number of elements in the array.

 
package{
  import flash.display.Sprite;
  
  public class Main extends Sprite{
    public function Main(){
        var aEmployees:Array = ["A", "P", "C", "H"];
        
        for(var i:Number = 0; i < aEmployees.length; i++) {
          trace(aEmployees[i]);
        }
    }
  }
}



Use the Array constructor allows you to specify the length of the new array.

 
package{
  import flash.display.Sprite;
  
  public class Main extends Sprite{
    public function Main(){
        var topTen:Array = new Array(10);
        // creates an array with 10 spaces.
        trace(topTen.length);
    }
  }
}