ActionScript的for循环

actionscript支持的for循环有三种形式:

1.for(初始值;条件;递增)

例如:

for(var x:int=1;x<=10;x++)
trace(x);

trace()会把结果输出到日志文件.

2.for(属性名 in 数组/对象)

例如:

var myArray:Array = ["alpha","beta","chi"];
for(var i:String in myArray){
trace(i);
}

循环是按照属性名迭代,而数组的属性名是数组的索引.因此输出结果为:

0

1

2

能够经过下面的方法取得值:

var myArray:Array = ["alpha","beta","chi"];
for(var i:String in myArray){
trace(myArray[i]);
}

为何变量i在这里是String而不是int?由于for...in循环返回的是属性名,而属性名是String;

若是在for...in循环中使用int,大多数状况下回出错.

访问对象与数组不一样的是,对象直接包含属性或特性,如:

var myObject:Object = {firstName:'Jeff',lastName:'Smith'};
for(var i:String in myObject){
trace("Property:"+i+"="+myObject[i]);
}

输出:

Property:firstName=Jeff

Property:lastName=Smith

3.for each(项 in 数组/对象)

for each...in循环用于迭代数组和对象,但测试的不是属性名,而是属性值

var myObject:Object = {firstName:'Jeff',lastName:'Smith'};
for each(var i:String in myObject){
trace(i);
}

输出:

Jeff

Smith