Javascript 找到对象的索引数组angularjs

find index of the object an array angularjs

提问by Edu Arif

for example I have this array :

例如我有这个数组：

  $scope.records = [
    {
      "Name" : "Alfreds Futterkiste",
      "Country" : "Germany"
    },
    {
      "Name" : "Berglunds snabbk?p",
      "Country" : "Sweden"
    },
    {
      "Name" : "Centro comercial Moctezuma",
      "Country" : "Mexico"
    },
    {
      "Name" : "Ernst Handel",
      "Country" : "Austria"
    }
  ];

How to get value index from object? with example "Country" : "Austria" this index is 3

如何从对象中获取值索引？例如“国家”：“奥地利”这个指数是 3

回答by adeneo

You could use Array.findIndexin the latest browsers, but there's no support for this in Internet Explorer, only Edge

您可以Array.findIndex在最新的浏览器中使用，但 Internet Explorer 不支持此功能，只有 Edge

let $scope = {};

$scope.records = [
    {
      "Name" : "Alfreds Futterkiste",
      "Country" : "Germany"
    },
    {
      "Name" : "Berglunds snabbk?p",
      "Country" : "Sweden"
    },
    {
      "Name" : "Centro comercial Moctezuma",
      "Country" : "Mexico"
    },
    {
      "Name" : "Ernst Handel",
      "Country" : "Austria"
    }
];

let index = $scope.records.findIndex( record => record.Country === "Austria" );

console.log(index); // 3

For support in IE9 and up, you could use Array.someinstead

对于 IE9 及更高版本的支持，您可以Array.some改用

var $scope = {};

$scope.records = [{
  "Name": "Alfreds Futterkiste",
  "Country": "Germany"
}, {
  "Name": "Berglunds snabbk?p",
  "Country": "Sweden"
}, {
  "Name": "Centro comercial Moctezuma",
  "Country": "Mexico"
}, {
  "Name": "Ernst Handel",
  "Country": "Austria"
}];

var index = -1;

$scope.records.some(function(obj, i) {
  return obj.Country === "Austria" ? index = i : false;
});

console.log(index);

回答by Rajesh

You can use array.findIndexfor this:

您可以array.findIndex为此使用：

var d = [{
  "Name": "Alfreds Futterkiste",
  "Country": "Germany"
}, {
  "Name": "Berglunds snabbk?p",
  "Country": "Sweden"
}, {
  "Name": "Centro comercial Moctezuma",
  "Country": "Mexico"
}, {
  "Name": "Ernst Handel",
  "Country": "Austria"
}];
var searchCountry = "Austria"
var index = d.findIndex(x=>x.Country === searchCountry)
console.log(index)

Note: array.findIndexis a part of ES6.

注意：array.findIndex是 ES6 的一部分。

回答by Chetan

Use findIndex method - 
   var index = $scope.records.findIndex(x=>x.Country==='Austria')

回答by randominstanceOfLivingThing

You can do which returns the countries and then finds the country.

您可以执行 which 返回国家，然后找到国家。

$scope.records.map((item) => { return item.Country;}).indexOf('Austria')

The problem with the above code iterates once through each element to generate a map and then finds the index. You can use a simple for loop:

上面代码的问题是遍历每个元素一次生成map，然后找到索引。您可以使用一个简单的 for 循环：

var index = (arr, k, v) => { 
   var i = -1;len = (arr || []).length;  
   for (i = 0; i < len; i++) { 
     if (arr[i][k] === v) 
       return i;
   }
   return -1;
} 

I noticed a lot of findIndex solutions. Please note: FindIndex method has been added to the ECMAScript 6 specification and may not be available in all JavaScript implementations yet as per MDN.

我注意到很多 findIndex 解决方案。请注意：FindIndex 方法已添加到 ECMAScript 6 规范中，根据 MDN，它可能尚未在所有 JavaScript 实现中可用。

You can use the polyfill for findIndex(https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findIndex) and use the findIndex solution that others suggested. If you do not want to use the polyfill you can use the map and indexOf that I put as solution.

您可以将 polyfill 用于 findIndex( https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findIndex) 并使用其他人建议的 findIndex 解决方案。如果你不想使用 polyfill，你可以使用我作为解决方案的 map 和 indexOf。

回答by Sid

Using a for - in loop as it is a JSON array, you can do this

使用 for - in 循环，因为它是一个 JSON 数组，你可以这样做

for(i in records) {
if(records[i].country=="Austria") 
console.log("index is :"+ parseInt(i)); // print index
}

回答by Siddharth

I have registered this method and it works like charm,

我已经注册了这个方法，它的作用就像魅力一样，

Array.prototype.getIndexByValue = function (name, value) {
        for (var i = 0, len=this.length; i <len; i++) {
            if (this[i][name]) {
                if (this[i][name] === value) {
                    return i
                }
            }
        }
        return -1;
    };

var d = [{
  "Name": "Alfreds Futterkiste",
  "Country": "Germany"
}, {
  "Name": "Berglunds snabbk?p",
  "Country": "Sweden"
}, {
  "Name": "Centro comercial Moctezuma",
  "Country": "Mexico"
}, {
  "Name": "Ernst Handel",
  "Country": "Austria"
}];


var index = d.getIndexByValue('Country','Austria');
console.log(index)//will print 3

回答by Makarov Sergey

function getIndexByCountryName(country)
    var found = $scope.records.find(function(item){return item.Country === country});
    return $scope.records.indexOf(found);
}