??
???????AS3中Object和 Dictionary都可以用来保存key-value形式的数据,Dictionary类和Object唯一的区别在于:Dictionary对象可以使用非字符串作为键值对的键。例如:
- var?obj:Object?=?new?Object();???
- obj["name"]?="name";???
- obj[1]?=?1;???
- obj[new?Object()]?="object";???
- for?(var?key:String?in?obj)?{???
- ????????trace(key+":"+obj[key]);???
- }??
var obj:Object = new Object();
obj["name"] ="name"; // key 字符串"name"
obj[1] = 1; // key是1 (被转换成字符串"1")
obj[new Object()] ="object"; // key是new Object(),被转传成字符串"[object Object]"
for (var key:String in obj) {
trace(key+":"+obj[key]); // 输出 1:1 [object Object]:object name:name
}
也就是说,无论用什么类型的变量作为键,Object都将key转换成字符串。同时,如果你使用了不同的对象作为键,都会被转换成字符串"[object Object]"作为键,因此而指向了同一个数据。例如:
- var?a:Object?=?new?Object();??????
- var?b:Object?=?new?Object();??????
- var?obj:Object?=?new?Object();??????
- obj[a]?=?1;???
- obj[b]?=?2;???
- for?(var?key:String?in?obj)?{??????
- ???????trace(key+":"+obj[key]);???
- }??
var a:Object = new Object();
var b:Object = new Object();
var obj:Object = new Object();
obj[a] = 1; // obj["[object Object]"] = 1;
obj[b] = 2; // obj["[object Object]"] = 2;
for (var key:String in obj) {
trace(key+":"+obj[key]); // traces: [object Object]:2
}
Dictionary类将没有这个限制,你可以将键设置成任何一种数据类型。例如:?
</pre><p>?</p><div class="dp-highlighter bg_javascript"><div class="bar"><div class="tools"><strong>[javascript]</strong> <a target=_blank title="view plain" class="ViewSource" href="http://blog.csdn.net/nsrainbow/article/details/6839497#">view plain</a><a target=_blank title="copy" class="CopyToClipboard" href="http://blog.csdn.net/nsrainbow/article/details/6839497#">copy</a><a target=_blank title="print" class="PrintSource" href="http://blog.csdn.net/nsrainbow/article/details/6839497#">print</a><a target=_blank title="?" class="About" href="http://blog.csdn.net/nsrainbow/article/details/6839497#">?</a></div></div><ol class="dp-c"><li class="alt"><span><span class="keyword">var</span><span>?a:Object?=?</span><span class="keyword">new</span><span>?Object();???</span></span></li><li><span><span class="keyword">var</span><span>?b:Object?=?</span><span class="keyword">new</span><span>?Object();???</span></span></li><li class="alt"><span><span class="keyword">var</span><span>?dict:Dictionary?=?</span><span class="keyword">new</span><span>?Dictionary();???</span></span></li><li><span>dict[a]?=?1;?<span class="comment">//?dict[a]?=?1;?</span><span>??</span></span></li><li class="alt"><span>dict[b]?=?2;?<span class="comment">//?dict[b]?=?2;?</span><span>??</span></span></li><li><span><span class="keyword">for</span><span>?(</span><span class="keyword">var</span><span>?key:*?</span><span class="keyword">in</span><span>?dict)?{???</span></span></li><li class="alt"><span>???????trace(key+<span class="string">":"</span><span>+dict[key]);?</span><span class="comment">//?traces:?[object?Object]:2?[object?Object]:1</span><span>??</span></span></li><li><span>}??</span></li></ol></div><pre class="javascript" style="display: none;" name="code">var a:Object = new Object();
var b:Object = new Object();
var dict:Dictionary = new Dictionary();
dict[a] = 1; // dict[a] = 1;
dict[b] = 2; // dict[b] = 2;
for (var key:* in dict) {
trace(key+":"+dict[key]); // traces: [object Object]:2 [object Object]:1
}
?
注意:
1、虽然在trace的时候,输出的还是[object Object],但是这个结果是对象的toString的结果。在Dictionary对象中,代表的是不同的对象引用。
2、这里的key的类型是*。这是很重要的,因为dict对象中的键可能是任何数据类型的。
?
?
3、Object的键必须是字符串,或表示字符串的表达式(变量或函数),若不是字符串的表达式,则将调用toString()方法,将其转化为字符串;
4、与Object不同的是,Dictionary使用的键是对象的引用,而不是字符串,且非原始对象键调用之前是通过全等运算符(===)来进行判断,并不会将数据类型强制转换之后再进行判断。