将对象的json数组中的值相加答案

【问题标题】：Sum the value from json array of object将对象的json数组中的值相加
【发布时间】：2017-02-22 07:42:27
【问题描述】：

{ "Chemistry - II": [ { "id": "9", "title": "Solid State", "quecount": 12 }, { "id": "10", "title": "Solutions", "quecount": 9 }, { "id": "11", "title": "Electrochemistry", "quecount": 8 }, { "id": "6", "title": "d and f- Block elements", "quecount": 42 } ], "Physics": [ { "id": "3", "title": "Circular Motion", "quecount": 5 } ] }

我正在尝试对“quecount”求和，但没有得到结果

$scope.chlist;
    for (i = 0; i < $scope.chlist.length; i++) 
    {  
        total += $scope.chlist[i].quecount; 
    }

    $scope.totque = total;

我们将不胜感激。谢谢。。

【问题讨论】：

您需要化学和物理的总和还是全部的总和？

标签： angularjs arrays json

【解决方案1】：

您可以使用Array.prototype.map() 和Array.prototype.reduce()

let chlist = {
  "Chemistry - II": [{
    "id": "9",
    "title": "Solid State",
    "quecount": 12
  }, {
    "id": "10",
    "title": "Solutions",
    "quecount": 9
  }, {
    "id": "11",
    "title": "Electrochemistry",
    "quecount": 8
  }, {
    "id": "6",
    "title": "d and f- Block elements",
    "quecount": 42
  }],
  "Physics": [{
    "id": "3",
    "title": "Circular Motion",
    "quecount": 5
  }]
};

Object.values(chlist).forEach(function(v){
  console.log(v.map(o => o.quecount).reduce((a,b) => a + b));
});

【讨论】：

【解决方案2】：

使用angular.forEach 循环遍历所有groups（例如：Chemistry - II），对于您要计算quecount 的每个组。

在您的控制器上：

$scope.chlist = {
    "Chemistry - II": [{
      "id": "9",
      "title": "Solid State",
      "quecount": 12
    }, {
      "id": "10",
      "title": "Solutions",
      "quecount": 9
    }, {
      "id": "11",
      "title": "Electrochemistry",
      "quecount": 8
    }, {
      "id": "6",
      "title": "d and f- Block elements",
      "quecount": 42
    }],
    "Physics": [{
      "id": "3",
      "title": "Circular Motion",
      "quecount": 5
    }]
 }

 var total = 0;
 angular.forEach($scope.chlist, function(value, key) {
   angular.forEach(value, function(item) {
     total += item.quecount;
    });
 });

 $scope.totque = total;

See JSFiddle

【讨论】：

【解决方案3】：

for (i = 0; i < $scope.chlist["Chemistry - II"].length; i++) {  
    total += $scope.chlist["Chemistry - II"][i].quecount;
}

尝试添加键-“化学-II”

【讨论】：

@PrashantFepale 更新了代码，为“for”和“total”添加了键

【解决方案4】：

var o = { "Chemistry - II": [ { "id": "9", "title": "Solid State", "quecount": 12 }, { "id": "10", "title": "Solutions", "quecount": 9 }, { "id": "11", "title": "Electrochemistry", "quecount": 8 }, { "id": "6", "title": "d and f- Block elements", "quecount": 42 } ], "Physics": [ { "id": "3", "title": "Circular Motion", "quecount": 5 } ] };

var total = 0;
for(var p in o) {
   if( Array.isArray(o[p]) ) {
      total = o[p].reduce((function(v, item) {
        return v + item.quecount;
      }, total);
   }   
}

【讨论】：

【解决方案5】：

试试这个：

var myApp = angular.module('myApp',[]);

myApp.controller('MyCtrl',function($scope) {
    
    $scope.jsonObj = {
	"Chemistry - II": [{
		"id": "9",
		"title": "Solid State",
		"quecount": 12
	}, {
		"id": "10",
		"title": "Solutions",
		"quecount": 9
	}, {
		"id": "11",
		"title": "Electrochemistry",
		"quecount": 8
	}, {
		"id": "6",
		"title": "d and f- Block elements",
		"quecount": 42
	}],
	"Physics": [{
		"id": "3",
		"title": "Circular Motion",
		"quecount": 5
	}]
};
    var chemistryQuecount = 0;
    var physicsQuecount = 0;
    for (var i in $scope.jsonObj) {
      if(i == 'Chemistry - II') {
        for(var j in $scope.jsonObj[i]) {
          chemistryQuecount += $scope.jsonObj[i][j].quecount;
        }
      }
      if(i == 'Physics') {
        for(var j in $scope.jsonObj[i]) {
          physicsQuecount += $scope.jsonObj[i][j].quecount;
        }
      }
    }
    console.log(chemistryQuecount);
    console.log(physicsQuecount);
});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="myApp" ng-controller="MyCtrl">
</div>

【讨论】：