Question

我想将对象更新为仅显示最近的一年，每年仅显示一次。

当前的股息变量为：

const data = {
    0: [
        'AAPL',
        0.378571,
        '2012-09-30'
    ],
    1: [
        'AAPL',
        0.378571,
        '2012-12-31'
    ],
    2: [
        'AAPL',
        0.378571,
        '2013-03-31'
    ],
    3: [
        'AAPL',
        0.435714,
        '2013-09-30'
    ],
    4: [
        'AAPL',
        0.435714,
        '2013-12-31'
    ],
    5: [
        'AAPL',
        0.47,
        '2014-09-30'
    ],
    6: [
        'AAPL',
        0.47,
        '2014-12-31'
    ],
    7: [
        'AAPL',
        0.52,
        '2015-06-30'
    ],
    8: [
        'AAPL',
        0.52,
        '2015-09-30'
    ],
    9: [
        'AAPL',
        0.52,
        '2015-12-31'
    ]
};

我想将变量更新为：

const dividends = {
    0: [
        'AAPL',
        0.378571,
        '2012-12-31'
    ],
    1: [
        'AAPL',
        0.435714,
        '2013-12-31'
    ],
    2: [
        'AAPL',
        0.47,
        '2014-12-31'
    ],
    3: [
        'AAPL',
        0.52,
        '2015-12-31'
    ]
};

很抱歉，由于错误导致stackoverflow不允许我发帖，因此不得不删除代码块格式

Answer 1

您可以使用array#reduce根据年份和对象中最早的日期对数据进行分组。然后使用Object.values()获取所有值。

const data = { 0: [ 'AAPL', 0.378571, '2012-09-30' ], 1: [ 'AAPL', 0.378571, '2012-12-31' ], 2: [ 'AAPL', 0.378571, '2013-03-31' ], 3: [ 'AAPL', 0.435714, '2013-09-30' ], 4: [ 'AAPL', 0.435714, '2013-12-31' ], 5: [ 'AAPL', 0.47, '2014-09-30' ], 6: [ 'AAPL', 0.47, '2014-12-31' ], 7: [ 'AAPL', 0.52, '2015-06-30' ], 8: [ 'AAPL', 0.52, '2015-09-30' ], 9: [ 'AAPL', 0.52, '2015-12-31' ] },
    result = Object.values(data).reduce((r,a) => {
      let year = a[2].substr(0,4);
      r[year] = r[year] || [...a];
      r[year] = r[year][2] > a[2] ? r[year]: [...a];
      return r;
    },{});
const dividends = {...Object.values(result)};
console.log(dividends);

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Answer 2

希望对您有帮助。

const data = {
    0: [
        'AAPL',
        0.378571,
        '2012-09-30'
    ],
    1: [
        'AAPL',
        0.378571,
        '2012-12-31'
    ],
    2: [
        'AAPL',
        0.378571,
        '2013-03-31'
    ],
    3: [
        'AAPL',
        0.435714,
        '2013-09-30'
    ],
    4: [
        'AAPL',
        0.435714,
        '2013-12-31'
    ],
    5: [
        'AAPL',
        0.47,
        '2014-09-30'
    ],
    6: [
        'AAPL',
        0.47,
        '2014-12-31'
    ],
    7: [
        'AAPL',
        0.52,
        '2015-06-30'
    ],
    8: [
        'AAPL',
        0.52,
        '2015-09-30'
    ],
    9: [
        'AAPL',
        0.52,
        '2015-12-31'
    ]
};

var years=[];
var result={};
var count=0;
for(var key in data){
  var arr=data[key];
  var year=arr[2].split("-")[0];
  if(years.indexOf(year)==-1){
    years.push(year);
    result[count]=arr;
    count++;
  }  
}
console.log(result);

Answer 3

您可以使用Object.values()将对象转换为数组，.filter()来检查原始数组Boolean的{{1}}日期字符串元素的.some()是否倒置对象Date等于迭代的当前元素，.getFullYear()大于当前元素，并且.getMonth()大于或等于当前元素，将结果数组传递到.getDate()将每个数组设置为JavaScript普通对象的基于0的属性

Object.assign()

Answer 4

您可以从右侧按日期减少排序的数据，并每年收集一次，仅对一个数据集进行分组。

const
    data = { 0: ['AAPL', 0.378571, '2012-09-30'], 1: ['AAPL', 0.378571, '2012-12-31'], 2: ['AAPL', 0.378571, '2013-03-31'], 3: ['AAPL', 0.435714, '2013-09-30'], 4: ['AAPL', 0.435714, '2013-12-31'], 5: ['AAPL', 0.47, '2014-09-30'], 6: ['AAPL', 0.47, '2014-12-31'], 7: ['AAPL', 0.52, '2015-06-30'], 8: ['AAPL', 0.52, '2015-09-30'], 9: ['AAPL', 0.52, '2015-12-31'] },
    years = {},
    result = Object.assign({}, Object.assign([], data).reduceRight((r, a) => {
        if (!years[a[2].slice(0, 4)] && !r.find(b => [0, 1].every(i => a[i] === b[i]))) {
            r.push(a);
            years[a[2].slice(0, 4)] = true;
        }
        return r;
    }, []).reverse());
   
console.log(result);

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如何分组年份并减少对象？

4 个答案: