Similar array of structures and objects

1, the choice of an array or object rule: When using an array sorting is required, otherwise use the object

1) When the property object named orderly numbers:

var obj1 = {
    "0":"zhansan",
    "1":"lisi",
    "2":"wangwu"
}

var arr1 = ["zhansan","lisi","wangwu"];

2) When a string array indices:

var arr2 = new Array();
arr2['a'] = [{name:"Adina",age:1},{name:"阿    化",age:6}];
arr2 is [ 'B'] = [{name: "Bora", age: 3}, { name: " Bo deep", Age:. 4 }];
arr2 is [ 'C'] = [{name: "Cao Xueqin", age: 5}, { name: " Cao", age: 6}];

was Obj2 = {
    a: [{name:"Adina",age:1},{name:"阿化",age:6}],
    b: [{name: "Bora", age: 3}, { name: " Bo deep", Age:. 4 }],
    c: [{name: "Cao Xueqin", age: 5}, { name: " Cao", Age:. 6 }]
}