Check if XML attribute is set?

I have a piece of code where I want to set a variable from an XML attribute only if that attribute is defined, otherwise do nothing.

Compare the following xml snippets:
<component name="gun" size="0">
vs.
<component name="armor">

In the example above, the "gun" has set the size and the "armor" has not.

How can I check whether an XML item (such as the two components above) has set a particular attribute (such as size)?

the long way to do it is as follows:

PHP Code:

---

var xml:XML = <root>
<component name="gun" size="0"></component>
<component name="gun"></component>
</root>;

var count:uint=xml.component.length();
while (count--){
    var size:String = xml.component[count].@size.toString();
    if(size.length > 0){
        trace("component " + count + " has size set.");
    };
} 


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however, you can grab all the components that have a size that meets a certain comparison really easily in an xml list, then perform actions on that list:

PHP Code:

---

var xml:XML = <root>
<component name="gun" size="0"></component>
<component name="gun" size="2"></component>
<component name="gun" size="5"></component>
<component name="gun" size="10"></component>
<component name="gun"></component>
<component name="gun"></component>
<component name="gun"></component>
</root>;

var hasguns:XMLList = xml.component.(attribute("size") > 1);
var count:uint=hasguns.length();
while (count--){
    trace(hasguns[count].@size);
} 


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PHP Code:

---

var list:XMLList =
XMLList(<component name="gun" size="0"/> +
<component name="armor"/>);
list.@*.(name() == "size" ? setSize(parent()) : "");
function setSize(value:XML):void
{
    trace("setting size of:", value.@name, "to:", value.@size);
} 


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