Question

在多维数组中修改深度值的最有效方法是什么？

我跟随json：

[
  {"name":"Series 1","data":[
    {"x":1506470700,"y":null},
    {"x":1506499200,"y":null},
    {"x":1506499500,"y":483981},
    {"x":1506499800,"y":504588},
    {"x":1506500100,"y":502926},
    {"x":1506500400,"y":501161},
    {"x":1506500700,"y":506453}]
  },{"name":"Series 2","data":[
    {"x":1506470700,"y":null},
    {"x":1506499200,"y":null},
    {"x":1506499500,"y":-490671},
    {"x":1506499800,"y":-495593},
    {"x":1506500100,"y":-512765},
    {"x":1506500400,"y":-479475},
    {"x":1506500700,"y":-531689}]
  }
]

我想将x值乘以1000.我可以使用此代码处理它，例如：

arrayFromJson.forEach((series) => {
    series.data.forEach((dataSet) => {
        dataSet.x *= 1000;
    });
});

但我想知道是否没有更有效/更优雅的方法来做到这一点。

Answer 1

使用数组映射：

var arr = [{"name":"Series 1","data":[{"x":1506470700,"y":null},{"x":1506499200,"y":null},{"x":1506499500,"y":483981},{"x":1506499800,"y":504588},{"x":1506500100,"y":502926},{"x":1506500400,"y":501161},{"x":1506500700,"y":506453}]},{"name":"Series 2","data":[{"x":1506470700,"y":null},{"x":1506499200,"y":null},{"x":1506499500,"y":-490671},{"x":1506499800,"y":-495593},{"x":1506500100,"y":-512765},{"x":1506500400,"y":-479475},{"x":1506500700,"y":-531689}]}];

arr.map(it => {
    it.data = it.data.map(dt => { dt.x = dt.x * 1000 ; return dt;})
});

console.log(arr);

Answer 2

您的解决方案完全没问题，但请记住，您正在改变原始数组，这可能会导致一些副作用。

对于不可变解决方案，请使用Array.prototype.map和Object.assign：

＆＃13;

var data = [{"name":"Series 1","data":[{"x":1506470700,"y":null},{"x":1506499200,"y":null},{"x":1506499500,"y":483981}]}];

var changedData = data.map(series => {
    return Object.assign({}, series, {
      data: series.data.map(dataSet => { 
        return Object.assign({}, dataSet, { x: dataSet.x * 1000 });
      })
    });
});

console.log(data);
console.log(changedData);

＆＃13;

Answer 3

你可以把它写得更短，没有一些括号和大括号。但是你仍然需要嵌套迭代。

arrayFromJson.forEach(series => series.data.forEach(dataSet => dataSet.x *= 1000));

Answer 4

假设您当前的代码完全正常，在es6上，一个（可能更快，更可读）的变体可能是

for( let series of arrayFromJson )
  for( let data of series.data )
    data.x *= 1000;

on es＆lt; 6，＆＃39; for in＆＃39;也会工作（假设您不需要有序遍历，但如果这些数组没有额外的自己的支柱......）

Javascript：在数组深处修改值

4 个答案: