Javascript 对象数组和唯一值

Question

我有一个看起来像这样的对象数组:

[
{"name":"Andrea","from":"USA","Food":"Candy"},
{"name":"Matt","from":"Taiwan","Food":"Chicken"},
{"name":"Roddy","from":"USA","Food":"Rice"},
{"name":"Andy","from":"Great Britain","Food":"Steak"},
];

有没有办法从上面的数组中获取所有国家的列表，并去掉重复的？

所以从上面的列表中，我要获取的列表是:

["USA", "Taiwan", "Great Britain"]

谢谢!

Answer 1

只需遍历 people 并在新数组中插入独特的国家/地区。这是一个例子。

var countries = [];

var people = [
{"name":"Andrea","from":"USA","Food":"Candy"},
{"name":"Matt","from":"Taiwan","Food":"Chicken"},
{"name":"Roddy","from":"USA","Food":"Rice"},
{"name":"Andy","from":"Great Britain","Food":"Steak"},
];

for (var i = 0, l=people.length; i < l; i++) {
    if(people[i] && people[i].from) {//ensure country exists
        if (countries.indexOf(people[i].from) == -1) {//ensure unique
             countries.push(people[i].from);
        }
    }
}