AS3：检查是否值是一个数字 [英] as3: check if value is a number

问题描述

我怎么能简单地检查返回的值是一个数字，即，12，12.5，12.75

how can i simply check if a returned value is a number i.e, 12 , 12.5, 12.75

if (_myValue == [[NUMBER]])
{
    fire()
}

推荐答案

简单：

if(_myValue is Number)
{
    fire();

}// end if

[更新]

请记住，如果 _myValue 的类型是 INT 或 UINT ，然后（_ myvalue的是Number）也将等同于真。如果你想知道，如果 _myValue 是一个数字，是不是整数（INT）或无符号整数（UINT），换言之花车，那么你可以简单地修改条件如下：

Keep in mind that if _myValue is of type int or uint, then (_myValue is Number) will also equate to true. If you want to know if _myValue is a number that isn't an integer(int) or unsigned integer (uint), in other words a float, then you can simply modify the conditional as follows:

(_myValue is Number && !(_myValue is int) && !(_myValue is uint))

让我们来看一个例子：

package 
{
    import flash.display.Sprite;
    import flash.events.Event;

    public class Main extends Sprite 
    {

        public function Main():void 
        {
            if (stage) init();
            else addEventListener(Event.ADDED_TO_STAGE, init);
        }

        private function init(e:Event = null):void 
        {
            removeEventListener(Event.ADDED_TO_STAGE, init);

            var number1:Object = 1; // int
            var number2:Object = 1.1; // float
            var number3:Object = 0x000000; // uint

            trace(number1 is Number); // true
            trace(number2 is Number); // true
            trace(number3 is Number); // true

            trace(number1 is Number && !(number1 is int) && !(number1 is uint)); // false
            trace(number2 is Number && !(number2 is int) && !(number2 is uint)); // true
            trace(number3 is Number && !(number3 is int) && !(number3 is uint)); // false

        }

    }

}

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