查找并替换多维数组中的每个元素 [关闭]答案

【问题标题】：Lookup and replace each element in a multidimensional array [closed]查找并替换多维数组中的每个元素 [关闭]
【发布时间】：2019-08-02 15:10:39
【问题描述】：

我有这个数组，它的第一列作为 id：

var mainarray = [
["1001","P6","P8"],
["1002","P7"],
["1003","P7","P8","P10"],
["1004","P6","P10"],
];

我想用下面“查找”数组中的相应动物替换每个“P”元素：

var arraylookup= [
["P6","dog"],
["P7","cat"],
["P8","mouse"],
["P9","horse"],
["P10","cow"],
];

...这将给我以下新数组

var newarray= [
["1001","dog","mouse"],
["1002","cat"],
["1003","cat","mouse","cow"],
["1004","dog","cow"],
];

我已经成功地把自己完全弄糊涂了。感谢您的帮助。

【问题讨论】：

arraylookup 数据格式使用起来可怕。你能修改那个对象吗？一个更简单的选项是这样的：{"P6":"dog","P7":"cat"}...
哦，这可能解释了为什么我还不能得到任何工作。是的，可以根据您的建议进行修改。
我确定有原因，但我看不出反对票的意义。我正在尝试在这里学习，我认为这是 SO 的重点。我没有提交任何尝试，因为我没有任何有价值的东西可以展示。不是抱怨，只是观察。

标签： javascript jquery arrays string multidimensional-array

【解决方案1】：

您可以在mainarray 上使用map 来将条目中的项目映射到它们的查找值。

要轻松查找值，请创建如下映射：

const lookup = {
  P6: "dog",
  P7: "cat",
  P8: "mouse",
  P9: "horse",
  P10: "cow"
};

您可以使用reduce 从您的arraylookup 数组中生成它。或者只是将arraylookup 重新格式化为代码中的对象。

您可以使用解构从数组条目中提取项目。

const arr = [
  ["1001","P6","P8"],
  ["1002","P7"],
  ["1003","P7","P8","P10"],
  ["1004","P6","P10"],
];
const arrLookup = [
  ["P6","dog"],
  ["P7","cat"],
  ["P8","mouse"],
  ["P9","horse"],
  ["P10","cow"],
];

const lookup = arrLookup.reduce((acc, [k, v]) => ({ ...acc, [k]: v }), {});

const result = arr.map(([id, ...rest]) => [id, ...rest.map(x => lookup[x])]);

console.log(result);

【讨论】：

【解决方案2】：

首先您应该将arraylookup 转换为一个对象，即：

const objLookUp= {
  "P6": "dog"],
  "P7": "cat",
  ...
};

const arrayLookUp= [
  ["P6","dog"],
  ["P7","cat"],
  ["P8","mouse"],
  ["P9","horse"],
  ["P10","cow"],
];

const objLookUp = arrayLookUp.reduce((r, [key, value]) => (r[key]= value, r), {});

console.log(objLookUp);

那么您将输入数组转换为所需的格式会容易得多：

const mainArray = [
  ["1001","P6","P8"],
  ["1002","P7"],
  ["1003","P7","P8","P10"],
  ["1004","P6","P10"],
];

const arrayLookUp= [
  ["P6","dog"],
  ["P7","cat"],
  ["P8","mouse"],
  ["P9","horse"],
  ["P10","cow"],
];

const objLookUp = arrayLookUp.reduce((r, [key, value]) => (r[key]= value, r), {});
const result = mainArray.map(
  arr => arr.map(v => v in objLookUp ? objLookUp[v] : v)
);

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

【讨论】：

【解决方案3】：

您可以像这样使用find 和map 和startsWith：

const array = [
  ["1001","P6","P8"],
  ["1002","P7"],
  ["1003","P7","P8","P10"],
  ["1004","P6","P10"],
];
const lookup = [
  ["P6","dog"],
  ["P7","cat"],
  ["P8","mouse"],
  ["P9","horse"],
  ["P10","cow"],
];

const result = array.map(arr => {
  let replaced = arr.map(s => {
    if (s.startsWith("P")) {
      var newValue = lookup.find(a => a[0] == s)[1];
      return newValue;
    }
    return s;
  });
  return replaced;
});

console.log(result);

等效于 ES5：

var array = [
  ["1001", "P6", "P8"],
  ["1002", "P7"],
  ["1003", "P7", "P8", "P10"],
  ["1004", "P6", "P10"],
];
var lookup = [
  ["P6", "dog"],
  ["P7", "cat"],
  ["P8", "mouse"],
  ["P9", "horse"],
  ["P10", "cow"],
];

var result = array.map(function(arr) {
  var replaced = arr.map(function(s) {
      if (s.startsWith("P")) {
        var newValue = lookup.find(function(a) {
            return a[0] == s;
        })[1];
      return newValue;
    }
    return s;
  });
return replaced;
});

console.log(result);

【讨论】：