Question

如果我有一个对象数组

[
    {name: 'John', count: 5, isunique: false, occupation: 'carpenter'}, 
    {name: 'Bob', count: 6,  isunique: false, occupation: 'carpenter'}, 
    {name: "John", count: 9, isunique: false, occupation: "barber"}
]

（这个数组很大），我想确定哪些职业是唯一的，并且在那个条件下返回一个新数组，其中只有boolean isunique被改变如下：

[
    {name: 'John', count: 5, isunique: false, occupation: 'carpenter'}, 
    {name: 'Bob', count: 6,  isunique: false, occupation: 'carpenter'}, 
    {name: "John", count: 9, isunique: true, occupation: "barber"}
]

这有可能在大型数组的Javascript中有效吗？我在这里完全不知所措。

Answer 1

您可以迭代数组并根据是否更改isunique属性，其他任何对象具有相同的职业，例如

arr.forEach(function(item) {
    item.isunique = !arr.some(function(item2) {
        return item !== item2 && item.occupation === item2.occupation;
    });
});

＆＃13;

var arr = [
    {name: 'John', count: 5, isunique: false, occupation: 'carpenter'}, 
    {name: 'Bob', count: 6,  isunique: false, occupation: 'carpenter'}, 
    {name: "John", count: 9, isunique: false, occupation: "barber"}
]

arr.forEach(function(item) {
    item.isunique = !arr.some(function(item2) {
    	return item !== item2 && item.occupation === item2.occupation;
    });
});

document.body.innerHTML = '<pre>' + JSON.stringify(arr, null, 4) + '</pre>'

＆＃13;

Answer 2

一个选项是：

var count = data.reduce(function(ret, el) {
    ret[el.occupation] = (ret[el.occupation] || 0) + 1;
    return ret;
}, {});

data.forEach(function(el) { el.isunique = count[el.occupation] === 1; });

如果对象值在数组中是唯一的，请执行此操作

2 个答案: