删除运算符
从对象中删除属性，从数组中移除元素或从 IDictionary 对象中移除项。
delete expression
参数
- 表达式
必选。 任何结果为属性引用、数组元素或 IDictionary 对象的表达式。
备注
如果表达式 的结果是一个对象，且在表达式 中指定的属性存在，同时该对象不允许此属性被删除，那么将返回 false。
在所有其他情况下，返回 true。
示例
下面的示例阐释 delete 运算符的一种用法。
// Make an object with city names and an index letter.
var cities : Object = {"a" : "Athens" , "b" : "Belgrade", "c" : "Cairo"}
// List the elements in the object.
var key : String;
for (key in cities) {
print(key + " is in cities, with value " + cities[key]);
}
print("Deleting property b");
delete cities.b;
// List the remaining elements in the object.
for (key in cities) {
print(key + " is in cities, with value " + cities[key]);
}
该代码的输出为：
a is in cities, with value Athens
b is in cities, with value Belgrade
c is in cities, with value Cairo
Deleting property b
a is in cities, with value Athens
c is in cities, with value Cairo