Question

我有一个这种形式的JSON数组

var data = [{"transDate":new Date("01/01/2018"),"temperature":95},
      {"transDate":new Date("02/01/2018"),"temperature":62},
      {"transDate":new Date("03/01/2018"),"temperature":51},
      {"transDate":new Date("04/01/2018"),"temperature":35},
      {"transDate":new Date("05/01/2018"),"temperature":95},
      {"transDate":new Date("06/01/2018"),"temperature":62},
      {"transDate":new Date("07/01/2018"),"temperature":51},
      {"transDate":new Date("08/01/2018"),"temperature":35},
      {"transDate":new Date("09/01/2018"),"temperature":95},
      {"transDate":new Date("10/01/2018"),"temperature":62},
      {"transDate":new Date("11/01/2018"),"temperature":51},
      {"transDate":new Date("12/01/2018"),"temperature":35},
      {"transDate":new Date("13/01/2018"),"temperature":95},
      {"transDate":new Date("14/01/2018"),"temperature":62},
      {"transDate":new Date("15/01/2018"),"temperature":51},
      {"transDate":new Date("16/01/2018"),"temperature":35},
      {"transDate":new Date("17/01/2018"),"temperature":95},
      {"transDate":new Date("18/01/2018"),"temperature":62},
      {"transDate":new Date("19/01/2018"),"temperature":51},
      {"transDate":new Date("20/01/2018"),"temperature":35},
      {"transDate":new Date("21/01/2018"),"temperature":95},
      {"transDate":new Date("22/01/2018"),"temperature":62},
      {"transDate":new Date("23/01/2018"),"temperature":51},
      {"transDate":new Date("24/01/2018"),"temperature":35},
      {"transDate":new Date("25/01/2018"),"temperature":95},
      {"transDate":new Date("26/01/2018"),"temperature":62},
      {"transDate":new Date("27/01/2018"),"temperature":51},
      {"transDate":new Date("28/01/2018"),"temperature":35}
    ];

现在我有一个这种形式的日期范围

01/01/2018 - 01/15/2018

我想从这个数据范围之间获取json数组中的所有数据。那么我如何使用切片函数做到这一点？

Answer 1

使用filter并将您的日期与startDate和endDate值进行比较。使用splice并不能真正实现所需的结果。

＆＃13;

var data = [{"transDate":new Date("01/01/2018"),"temperature":95},
      {"transDate":new Date("02/01/2018"),"temperature":62},
      {"transDate":new Date("01/10/2018"),"temperature":51},
      {"transDate":new Date("04/01/2018"),"temperature":35},
      {"transDate":new Date("05/01/2018"),"temperature":95},
      {"transDate":new Date("06/01/2018"),"temperature":62},
      {"transDate":new Date("07/01/2018"),"temperature":51},
      {"transDate":new Date("08/01/2018"),"temperature":35},
      {"transDate":new Date("09/01/2018"),"temperature":95},
      {"transDate":new Date("10/01/2018"),"temperature":62},
      {"transDate":new Date("11/01/2018"),"temperature":51},
      {"transDate":new Date("12/01/2018"),"temperature":35},
      {"transDate":new Date("13/01/2018"),"temperature":95},
      {"transDate":new Date("14/01/2018"),"temperature":62},
      {"transDate":new Date("15/01/2018"),"temperature":51},
      {"transDate":new Date("16/01/2018"),"temperature":35},
      {"transDate":new Date("17/01/2018"),"temperature":95},
      {"transDate":new Date("18/01/2018"),"temperature":62},
      {"transDate":new Date("19/01/2018"),"temperature":51},
      {"transDate":new Date("20/01/2018"),"temperature":35},
      {"transDate":new Date("21/01/2018"),"temperature":95},
      {"transDate":new Date("22/01/2018"),"temperature":62},
      {"transDate":new Date("23/01/2018"),"temperature":51},
      {"transDate":new Date("24/01/2018"),"temperature":35},
      {"transDate":new Date("25/01/2018"),"temperature":95},
      {"transDate":new Date("26/01/2018"),"temperature":62},
      {"transDate":new Date("27/01/2018"),"temperature":51},
      {"transDate":new Date("28/01/2018"),"temperature":35}
    ];

var startDate = '01/01/2018';
var endDate = '01/15/2018';

var res = data.filter(dateObj => new Date(startDate) <dateObj.transDate && dateObj.transDate<new Date(endDate));
console.log(res);

＆＃13;

Answer 2

那么我如何使用切片功能呢？

要使slice生效，您需要起始索引和结束索引的索引。使用findIndex表示相同的内容（ 假设数据按日期按升序排序 ）

var startDate = "01/01/2018";
var endDate = "01/15/2018";
var fnIsGreaterOrEqual = (dateObj, dateStr) => {}; //logic for date comparison
var startIndex = data.findIndex( s => fnIsGreaterOrEqual(s.transDate, startDate) );
var endIndex = data.findIndex( s => fnIsGreaterOrEqual(s.transDate, endDate) );
var output = data.slice(startIndex, endIndex);

但是，推荐的解决方案将使用filter本身

var fnToDateObj = (dateStr) => {}; //logic for date conversion
var startDate = fnToDateObj("01/01/2018");
var endDate = fnToDateObj("15/01/2018");
var output = data.filter( s => s.transDate >= startDate && s.transDate <= endDate );

如何使用切片获取给定范围之间的数据

2 个答案: