Question

怎样快速而优雅地遍历 JavaScript 数组

Answer 1

//----------------for用来遍历数组对象--
var i,myArr = [1,2,3];
for (var i = 0; i < myArr.length; i++) {
console.log(i+":"+myArr[i]);
};
//---------for-in 用来遍历非数组对象
var man ={hands:2,legs:2,heads:1};
//为所有的对象添加clone方法，即给内置原型(object,Array,function)增加原型属性,该方法很强大，也很危险
if(typeof Object.prototype.clone ==="undefined"){
Object.prototype.clone = function(){};
}
//
for(var i in man){
if (man.hasOwnProperty(i)) { //filter,只输出man的私有属性
console.log(i,":",man[i]);
};
}
//输出结果为print hands:2,legs:2,heads:1

for(var i in man) {//不使用过滤
console.log(i,":",man[i]);
}
//输出结果为
//hands : 2 index.html:20
//legs : 2 index.html:20
//heads : 1 index.html:20
//clone : function (){}
for(var i in man) {
if(Object.prototype.hasOwnProperty.call(man,i)) { //过滤
console.log(i,":",man[i]);
}
}
//输出结果为print hands:2,legs:2,heads:1