javascript - 通过匹配值数组来对 javascript 对象文字进行子集化

Question

我需要对对象文字进行子集化 myData那些属于 group 的元素B 和 year匹配 group 中找到的内容答:

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}] ;

我可以使用.filter()获得所需的输出:

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

结果:

[{"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}];

但这并不理想。我想要一个通用的、通用的解决方案，不依赖于“手动”输入最大值 (6)。另外，year可能不是一个序列(例如 [2, 1, 4, 5] )。

本质上，障碍在于条件的第二部分 ( d.year < 6 )。我需要一些与以下位置的值相匹配的东西:

let x = []

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

谢谢!

Answer 1

你已经成功了一半；现在您已经有了“A”组中所有年份的数组，您只需检查“B”组中的年份是否在该数组中。您可以使用 .includes() 来实现此目的。

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