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通过匹配值数组来子集javascript对象文本

filter javascript

JdeMello · 技术社区 · 6 年前

myData 这些元素属于 group B类和 year 匹配那些在 组

var myData = [{"year":1,"group":"A","value":0.1},
 {"year":2,"group":"A","value":0.2},
 {"year":3,"group":"A","value":0.2},
 {"year":4,"group":"A","value":0.1},
 {"year":5,"group":"A","value":0.1},
 {"year":1,"group":"B","value":0.1},
 {"year":2,"group":"B","value":0.2},
 {"year":3,"group":"B","value":0.2},
 {"year":4,"group":"B","value":0.2},
 {"year":5,"group":"B","value":0.9},
 {"year":6,"group":"B","value":0.1}] ;

我可以用 .filter() 要获得所需的输出:

mySubset = myData.filter((d) => {return d.group == "B" && d.year < 6;});

[{"year":1,"group":"B","value":0.1},
  {"year":2,"group":"B","value":0.2},
  {"year":3,"group":"B","value":0.2},
  {"year":4,"group":"B","value":0.2},
  {"year":5,"group":"B","value":0.9}];

年 [2, 1, 4, 5]

d.year < 6

let x = []

for(i = 0; i < myData.filter((d) => {return d.group == "A";}).length; i++){
    x.push(myData[i].year);
}

谢谢您!

3 回复 | 直到 6 年前

AsherMaximum 6 年前

您已经完成了一半;现在您已经有了一个数组,其中包含了“A”组中的所有年份,您只需要检查“B”组中的年份是否在该数组中。你可以用 .includes() 为了这个。

mySubset = myData.filter((d) => {return d.group == "B" && x.includes(d.year);});

amrender singh 6 年前

Set 其中包含了所有的年组 A

var myData = [{"year":1,"group":"A","value":0.1}, {"year":2,"group":"A","value":0.2}, {"year":3,"group":"A","value":0.2}, {"year":4,"group":"A","value":0.1}, {"year":5,"group":"A","value":0.1}, {"year":1,"group":"B","value":0.1}, {"year":2,"group":"B","value":0.2}, {"year":3,"group":"B","value":0.2}, {"year":4,"group":"B","value":0.2}, {"year":5,"group":"B","value":0.9}, {"year":6,"group":"B","value":0.1}];

let set = new Set(myData.filter(e=>e.group =="A").map(e=>e.year));

let result = myData.filter(e=> e.group =="B" && set.has(e.year));

console.log(result);

Francis Leigh 6 年前

通过做一个 getSubset()

我还过滤掉yearGroups数组中任何可能为空的数组,以防年份不匹配

let myData = [
 {"year":1,"group":"A","value":0.1},
 {"year":2,"group":"A","value":0.2},
 {"year":3,"group":"A","value":0.2},
 {"year":4,"group":"A","value":0.1},
 {"year":5,"group":"A","value":0.1},
 {"year":1,"group":"B","value":0.1},
 {"year":2,"group":"B","value":0.2},
 {"year":3,"group":"B","value":0.2},
 {"year":4,"group":"B","value":0.2},
 {"year":5,"group":"B","value":0.9},
 {"year":6,"group":"B","value":0.1}
]


let getSubsets = (group = 'B', year = 6) => myData.filter(d => d.group == group && d.year < year)

console.log(getSubsets())

console.log(getSubsets('A', 4))

let yearGroups = [1,2,3,4,5].map(y => getSubsets('B', y)).filter(a => !!a.length)

console.log(yearGroups)