Question

我有以下物品，我想总结相同成分名称的值，如：番茄：5，鸡肉：5，米饭：1，豌豆：1，我有这个代码，但没有总和，而是显示所有对象

var data3 = {
  "menus": [{
    "recipe": "chicken with rice",
    "ingredients": [{
      "name": "tomato",
      "value": 2
    }, {
      "name": "chicken",
      "value": 3
    }, {
      "name": "rice",
      "value": 1
    }]
  }, {
    "recipe": "Garden rice",
    "ingredients": [{
      "name": "tomato",
      "value": 3
    }, {
      "name": "chicken",
      "value": 2
    }, {
      "name": "peas",
      "value": 1
    }]
  }]
};

var ingredients;

for (var i = 0; i < 10; i++) {
  ingredients = data3.menus[i].ingredients;

  var temp = {};
  var obj = null;
  for (var j = 0; j < ingredients.length; j++) {
    obj = ingredients[j];

    if (!temp[obj.name]) {
      temp[obj.name] = obj;
    } else {
      temp[obj.name].value += obj.value;
    }

  }
  var result = [];
  for (var prop in temp)
     result.push(temp[prop]);

  console.log(result);

};

感谢您的帮助，谢谢！

Answer 1

如果属性不存在，您可以使用带有成分名称的哈希表，并使用默认值零。然后添加值。

＆＃13;

var data3 = { menus: [{ recipe: "chicken with rice", ingredients: [{ name: "tomato", value: 2 }, { name: "chicken", value: 3 }, { name: "rice", value: 1 }] }, { recipe: "Garden rice", ingredients: [{ name: "tomato", value: 3 }, { name: "chicken", value: 2 }, { name: "peas", value: 1 }] }] },
    ingredients = Object.create(null);

data3.menus.forEach(function (a) {
    a.ingredients.forEach(function (b) {
        ingredients[b.name] = (ingredients[b.name] || 0) + b.value;
    });
});

console.log(ingredients);

＆＃13;

Answer 2

你的实现是正确的，只是你一次又一次地重新初始化temp。所以你只需要从你的for循环中取出temp。

var data3 = {
  "menus": [{
    "recipe": "chicken with rice",
    "ingredients": [{
      "name": "tomato",
      "value": 2
    }, {
      "name": "chicken",
      "value": 3
    }, {
      "name": "rice",
      "value": 1
    }]
  }, {
    "recipe": "Garden rice",
    "ingredients": [{
      "name": "tomato",
      "value": 3
    }, {
      "name": "chicken",
      "value": 2
    }, {
      "name": "peas",
      "value": 1
    }]
  }]
};

var ingredients;
var temp = {};
for (var i = 0; i < data3.menus.length; i++) {
  ingredients = data3.menus[i].ingredients;

  var obj = null;
  for (var j = 0; j < ingredients.length; j++) {
    obj = ingredients[j];


    if (!temp[obj.name]) {
      temp[obj.name] = obj;
    } else {
      temp[obj.name].value += obj.value;
    }
  }
};

var result = [];
  for (var prop in temp)
     result.push(temp[prop]);
  console.log(result);

Answer 3

您可以创建一个将遍历所有成分的函数，如果ingredient.name已给出名称，则将ingredient.value添加到结果中。这是带有箭头功能的ES2015解决方案：

const sumIngredients = (menus, name) => {
  let result = 0;
  menus.forEach(meal => {
    meal.ingredients.forEach(ingredient => {
      if (ingredient.name === name) {
        result += ingredient.value;
      }
    })
  })
  return result;
}

使用它：

sumIngredients(data3.menus, 'chicken'); //5
sumIngredients(data3.menus, 'tomato'); //5 
sumIngredients(data3.menus, 'rice'); //1
sumIngredients(data3.menus, 'peas'); //1

工作示例：https://jsfiddle.net/sc8wrupk/

Javascript对象和相同属性键的值

3 个答案: