package { import flash.display.*; import flash.events.*; import flash.text.*; import flash.utils.*; public class Main extends Sprite { static private const _NUM_TIMES:uint = 1000000; private function _init():void { _debug( "各テスト " + _NUM_TIMES + " 回処理させた計算結果 [単位 : ミリ秒]\n" + "(誤差は多少生じます)\n" ); var n:uint = 10; _measure("ループのみ", function ():void { for (var i:uint = 0; i < _NUM_TIMES; i++) { } }); _measure("1 回のみ比較する if ... else 文", function ():void { for (var i:uint = 0; i < _NUM_TIMES; i++) { if (n === 0) {} else {} } }); _measure("1 回のみ比較する switch 文", function ():void { for (var i:uint = 0; i < _NUM_TIMES; i++) { switch (n) { case 0: break; default: break; } } }); _measure("10 回比較する if ... else 文", function ():void { for (var i:uint = 0; i < _NUM_TIMES; i++) { if (n === 0) {} else if (n === 1) {} else if (n === 2) {} else if (n === 3) {} else if (n === 4) {} else if (n === 5) {} else if (n === 6) {} else if (n === 7) {} else if (n === 8) {} else if (n === 9) {} else {} } }); _measure("10 回比較する switch 文", function ():void { for (var i:uint = 0; i < _NUM_TIMES; i++) { switch (n) { case 0: break; case 1: break; case 2: break; case 3: break; case 4: break; case 5: break; case 6: break; case 7: break; case 8: break; case 9: break; default: break; } } }); _debug("\n結果については言及しませんので, 各自ご判断ください."); } private var _field:TextField; private var _time:uint; public function Main():void { _setup(); _init(); } private function _measure(title:String, func:Function, ...params):void { _time = getTimer(); func.apply(null, params); _time = getTimer() - _time; _debug("[ " + title + " ] --> " + _time + " ms"); } private function _debug(log:String):void { _field.appendText(log + "\n"); } private function _setup():void { _field = new TextField(); _field.width = stage.stageWidth - 40; _field.height = stage.stageHeight - 60; _field.x = 20; _field.y = 60; _field.multiline = true; _field.wordWrap = true; var format:TextFormat = _field.defaultTextFormat; format.font = "_sans"; _field.defaultTextFormat = format; addChild(_field); var button:Sprite = new Sprite(); button.graphics.lineStyle(1, 0xBBBBBB); button.graphics.beginFill(0xEEEEEE); button.graphics.drawRoundRect(0, 0, 100, 20, 5, 5); button.graphics.endFill(); addChild(button); button.x = 20; button.y = 20; button.mouseChildren = false; button.buttonMode = true; var field:TextField = new TextField(); field.width = 100; field.height = 20; field.htmlText = "<p align='center'><font face='_sans'>再計算</span></p>"; button.addChild(field); button.addEventListener(MouseEvent.CLICK, function ():void { _field.text = ""; _init(); }); } } } [最適化 Tips] if ... else と switch での処理速度の違い