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法律研究从对象的 javascript 数组中获取前 n 项最大值
假设我们有一个这样的对象数组 −
const arr = [
{"id":0,"start":0,"duration":117,"slide":4,"view":0},
{"id":0,"start":0,"duration":12,"slide":1,"view":0},
{"id":0,"start":0,"duration":41,"slide":2,"view":0},
{"id":0,"start":0,"duration":29,"slide":3,"view":0},
{"id":0,"start":0,"duration":123,"slide":3,"view":0},
{"id":0,"start":0,"duration":417,"slide":2,"view":0},
{"id":0,"start":0,"duration":12,"slide":1,"view":0},
{"id":0,"start":0,"duration":67,"slide":2,"view":0}
];我们必须编写一个函数，它接受这个数组，并在另一个数组中返回该数组的前 n 个元素（前 n 个表示 duration 值最高的对象）。
因此，让我们为这个问题编写代码 −
示例
const arr = [
{"id":0,"start":0,"duration":117,"slide":4,"view":0},
{"id":0,"start":0,"duration":12,"slide":1,"view":0},
{"id":0,"start":0,"duration":41,"slide":2,"view":0},
{"id":0,"start":0,"duration":29,"slide":3,"view":0},
{"id":0,"start":0,"duration":123,"slide":3,"view":0},
{"id":0,"start":0,"duration":417,"slide":2,"view":0},
{"id":0,"start":0,"duration":12,"slide":1,"view":0},
{"id":0,"start":0,"duration":67,"slide":2,"view":0}
];
const topN = (arr, n) => {
if(n > arr.length){
return false;
}
return arr
.slice()
.sort((a, b) => {
return b.duration - a.duration
})
.slice(0, n);
};
console.log(topN(arr, 3));
console.log(topN(arr, 4));
console.log(topN(arr, 5));输出
控制台中的输出将为 −
[
{ id: 0, start: 0, duration: 417, slide: 2, view: 0 },
{ id: 0, start: 0, duration: 123, slide: 3, view: 0 },
{ id: 0, start: 0, duration: 117, slide: 4, view: 0 }
]
[
{ id: 0, start: 0, duration: 417, slide: 2, view: 0 },
{ id: 0, start: 0, duration: 123, slide: 3, view: 0 },
{ id: 0, start: 0, duration: 117, slide: 4, view: 0 },
{ id: 0, start: 0, duration: 67, slide: 2, view: 0 }
]
[
{ id: 0, start: 0, duration: 417, slide: 2, view: 0 },
{ id: 0, start: 0, duration: 123, slide: 3, view: 0 },
{ id: 0, start: 0, duration: 117, slide: 4, view: 0 },
{ id: 0, start: 0, duration: 67, slide: 2, view: 0 },
{ id: 0, start: 0, duration: 41, slide: 2, view: 0 }
]
更新于: 26-Aug-2020
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