2018-10-10 18:03:03 -04:00
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---
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id: 595011cba5a81735713873bd
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2020-12-16 00:37:30 -07:00
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title: 每组排名最高
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2018-10-10 18:03:03 -04:00
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challengeType: 5
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videoUrl: ''
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---
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2020-12-16 00:37:30 -07:00
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# --description--
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任务:
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在每个组中查找排名前N位的数据,其中N作为参数提供。等级和组的名称也作为参数提供。
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鉴于以下数据:
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```
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[
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{姓名:'Tyler Bennett',id:'E10297',薪水:32000,部门:'D101'},
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{姓名:'John Rappl',id:'E21437',薪水:47000,部门:'D050'},
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{姓名:'George Woltman',id:'E00127',薪水:53500,部门:'D101'},
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{name:'Adam Smith',id:'E63535',薪水:18000,部门:'D202'},
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{姓名:'Claire Buckman',id:'E39876',薪水:27800,部门:'D202'},
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{姓名:'David McClellan',id:'E04242',薪水:41500,部门:'D101'},
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{name:'Rich Holcomb',id:'E01234',薪水:49500,dept:'D202'},
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{姓名:'Nathan Adams',id:'E41298',薪水:21900,部门:'D050'},
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{姓名:'Richard Potter',id:'E43128',薪水:15900,部门:'D101'},
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{姓名:'David Motsinger',id:'E27002',薪水:19250,dept:'D202'},
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{姓名:'Tim Sampair',id:'E03033',薪水:27000,部门:'D101'},
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{姓名:'Kim Arlich',id:'E10001',薪水:57000,部门:'D190'},
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{name:'Timothy Grove',id:'E16398',薪水:29900,部门:'D190'}
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2018-10-10 18:03:03 -04:00
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]。
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2020-12-16 00:37:30 -07:00
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```
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</pre>通过调用<code>topRankPerGroup(10, data, 'dept', 'salary')</code>可以对每个部门的前10名员工进行排名。给出以下数据: <pre> [
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{name:'Friday 13th',类型:'恐怖',评分:9.9},
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{姓名:“榆树街上的梦魇”,类型:'恐怖',等级:5.7},
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{name:'Titanic',类型:'drama',评分:7.3},
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{name:'Maze Runner',类型:'scifi',评级:7.1},
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{name:'Blade runner',类型:'scifi',评分:8.9}
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2018-10-10 18:03:03 -04:00
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]。
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2020-12-16 00:37:30 -07:00
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</pre>通过调用<code>topRankPerGroup(1, data, 'genre', 'rating')</code>可以在每个类型中对排名最高的电影进行排名
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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# --hints--
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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`topRankPerGroup`是一个函数。
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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```js
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assert(typeof topRankPerGroup === 'function');
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```
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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`topRankPerGroup`在负n值上返回undefined。
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2018-10-10 18:03:03 -04:00
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```js
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2020-12-16 00:37:30 -07:00
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assert(typeof topRankPerGroup(-1, []) === 'undefined');
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```
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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第一部门必须是D050
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```js
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assert.equal(res1[0][0].dept, 'D050');
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2018-10-10 18:03:03 -04:00
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```
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2020-12-16 00:37:30 -07:00
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第一部门必须是D050
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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```js
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assert.equal(res1[0][1].salary, 21900);
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```
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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最后一个部门必须是D202
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2018-10-10 18:03:03 -04:00
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```js
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assert.equal(res1[3][3].dept, 'D202');
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2018-10-10 18:03:03 -04:00
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```
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2020-12-16 00:37:30 -07:00
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`topRankPerGroup(1, ...)`必须仅返回每组的排名最高的结果。
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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```js
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assert.equal(res2[2].length, 1);
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```
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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`topRankPerGroup(1, ...)`必须仅返回每组的排名最高的结果。
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2018-10-10 18:03:03 -04:00
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```js
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2020-12-16 00:37:30 -07:00
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assert.equal(res3[2][1].name, 'Maze Runner');
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2018-10-10 18:03:03 -04:00
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```
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2020-08-13 17:24:35 +02:00
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2020-12-16 00:37:30 -07:00
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# --solutions--
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