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  • new Set()

    Set 对象存储的值总是唯一的,可以用来去重数组。

    Set 对象作用

    1.数组去重

    var arr = [1,2,3,3,1,4];
    [...new Set(arr)]; // [1, 2, 3, 4]
    Array.from(new Set(arr)); // [1, 2, 3, 4]
    [...new Set('ababbc')].join(''); // "abc" 字符串去重
    new Set('ice doughnut'); //Set(11) {"i", "c", "e", " ", "d", "o","u","g","h","n","u","t"}

    2.并集

    var a = new Set([1, 2, 3]);
    var b = new Set([4, 3, 2]);
    var union = new Set([...a, ...b]); // {1, 2, 3, 4}

    3.交集

    var a = new Set([1, 2, 3]);
    var b = new Set([4, 3, 2]);
    var intersect = new Set([...a].filter(x => b.has(x))); // {2, 3}

    4.差集

    var a = new Set([1, 2, 3]);
    var b = new Set([4, 3, 2]);
    var difference = new Set([...a].filter(x => !b.has(x))); // {1}
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  • 原文地址:https://www.cnblogs.com/helloyoyo/p/14900559.html
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