[AS3]for 循环数组的效率测试

循环 ("abcdefghijklmnopqrstuvwxyz").split("") 这个数组 100000 次的结果：(单位：ms)

No.	for 循环	for..in 循环	for each 循环
1	17	8213	2165
2	19	8126	2188
3	18	8338	2128
4	18	7100	2409
5	17	8054	2945
平均	17.8	7900.2	2367.0
偏差(越小越稳定)	0.748	443.326	305.225

测试程序：

源码：

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical"
 scriptTimeLimit="10"
 width="520" height="490">
 <mx:Script>
 <![CDATA[
 
 private static const FOR:String = "for 循环";
 private static const FOR_IN:String = "for..in 循环";
 private static const FOR_EACH:String = "for each 循环"
 private static var LOOP_SRC:Array = ("abcdefghijklmnopqrstuvwxyz").split("");
 
 private function test(testCase:String):void {
  var loopCount:int = int(count_ns.value);
  var start:int, now:int;
  var i:int;
  output("@" + testCase);
  try {
   switch (testCase) {
    case FOR:
     start = getTimer();
     for (i = 0; i < loopCount; i++) {
      //var length:int = LOOP_SRC.length;
      for(var j:int; j<LOOP_SRC.length; j++) {
       LOOP_SRC[j].toUpperCase();
      }
     }
     now = getTimer();
     break;
    case FOR_IN:
     start = getTimer();
     for (i = 0; i < loopCount; i++) {
      for(var j2:String in LOOP_SRC) {
       LOOP_SRC[j2].toUpperCase();
      }
     }
     now = getTimer();
     break;
    case FOR_EACH:
     start = getTimer();
     for (i = 0; i < loopCount; i++) {
      for each(var v:String in LOOP_SRC) {
       v.toUpperCase();
      }
     }
     now = getTimer();
     break;
   }
  }
  catch (e:Error) {
   now = getTimer();
   output("  " + i + "次时弹出错误: " + e);
  }
  var time:int = now - start;
  output("  经过时间(ms): " + nf.format(time));
  output("  1秒中的循环次数: " + nf.format(i * 1000 / time));
  output("----------------------------------------");
 }

 private function output(msg:String):void {
  output_ta.text += msg + "\n";
 }
 ]]>
 </mx:Script>
 
 <mx:NumberFormatter id="nf" precision="0" />
 <mx:Panel title="循环数组的压力测试"
  paddingTop="8" paddingRight="8" paddingBottom="8" paddingLeft="8">
  <mx:HBox>
   <mx:Label text="循环回数:" />
   <mx:NumericStepper id="count_ns" value="100000" maximum="10000000" />
  </mx:HBox>
  <mx:HBox>
   <mx:Button label="{FOR}" click="test(FOR)" />
   <mx:Button label="{FOR_IN}" click="test(FOR_IN)" />
   <mx:Button label="{FOR_EACH}" click="test(FOR_EACH)" />
  </mx:HBox>
  <mx:TextArea id="output_ta" width="400" height="300" />
  <mx:Label color="red" text="*Application.scriptTimeLimit设为了10秒。" />
 </mx:Panel>
</mx:Application>