計數JSON節點不工作

好吧，我有以下JSON代碼：計數JSON節點不工作

{ 
"productDetails": { 
    "productThumb": "/uploads/[email protected]/showup-bg4.jpg", 
    "productName": "Hamburger", 
    "productDesc": "Made with 100% American ground beef", 
    "productPrice": "9.99", 
    "productModifiers": [{ 
     "Sides": [{ 
      "modifierName": "Applesauce", 
      "modifierUpcharge": "0", 
      "isDefault": "off" 
     },{ 
      "modifierName": "Rice", 
      "modifierUpcharge": "0", 
      "isDefault": "off" 
     }], 
     "Toppings": [{ 
      "modifierName": "Bacon", 
      "modifierUpcharge": "0.25", 
      "isDefault": "off" 
     }, { 
      "modifierName": "Tomato", 
      "modifierUpcharge": "0", 
      "isDefault": "on" 
     }], 
     "Doneness": [{ 
      "modifierName": "Extra Well", 
      "modifierUpcharge": "0", 
      "isDefault": "off" 
     },{ 
      "modifierName": "Well", 
      "modifierUpcharge": "0", 
      "isDefault": "off" 
     }], 
     "Breads": [{ 
      "modifierName": "White Bun", 
      "modifierUpcharge": "0", 
      "isDefault": "on" 
     }, { 
      "modifierName": "Whole Wheat Bun", 
      "modifierUpcharge": "0", 
      "isDefault": "off" 
     }] 
    }] 
} 
}

我跑它通過jsonlint.com並驗證它回來作爲有效的JSON。在我的jQuery，我有以下代碼：

$.ajax({ 
    url: "/getItemDetails/"+productType+"/"+productID, 
    type: "get", 
    data: ({productType:productType, productID:productID}), 
    dataType: "json", 
    success: function(data) { 
     var numMods = data.productDetails.productModifiers.length; 
     console.log("There are "+numMods+" categories of modifiers."); 
    } 
});

由於某些原因，但是，我的console.log返回爲未定義。基本上，我需要知道productModifiers節點內有多少「類別」。所以在這種情況下，它應該返回4（側面，澆頭，完整和麪包）。我似乎無法弄清楚我缺少的東西，這將使我能夠弄清楚有多少個子節點

來源

2017-02-15 John Hubler

的問題是，productModifiers是與它一個對象，它包含了你所需要的類別多鍵的數組。因此，下面是你需要的代碼。如果productModifiers的對象多於1個，則需要遍歷對象來計算類別。

var json = { 
 
    "productDetails": { 
 
    "productThumb": "/uploads/[email protected]/showup-bg4.jpg", 
 
    "productName": "Hamburger", 
 
    "productDesc": "Made with 100% American ground beef", 
 
    "productPrice": "9.99", 
 
    "productModifiers": [{ 
 
     "Sides": [{ 
 
     "modifierName": "Applesauce", 
 
     "modifierUpcharge": "0", 
 
     "isDefault": "off" 
 
     }, { 
 
     "modifierName": "Rice", 
 
     "modifierUpcharge": "0", 
 
     "isDefault": "off" 
 
     }], 
 
     "Toppings": [{ 
 
     "modifierName": "Bacon", 
 
     "modifierUpcharge": "0.25", 
 
     "isDefault": "off" 
 
     }, { 
 
     "modifierName": "Tomato", 
 
     "modifierUpcharge": "0", 
 
     "isDefault": "on" 
 
     }], 
 
     "Doneness": [{ 
 
     "modifierName": "Extra Well", 
 
     "modifierUpcharge": "0", 
 
     "isDefault": "off" 
 
     }, { 
 
     "modifierName": "Well", 
 
     "modifierUpcharge": "0", 
 
     "isDefault": "off" 
 
     }], 
 
     "Breads": [{ 
 
     "modifierName": "White Bun", 
 
     "modifierUpcharge": "0", 
 
     "isDefault": "on" 
 
     }, { 
 
     "modifierName": "Whole Wheat Bun", 
 
     "modifierUpcharge": "0", 
 
     "isDefault": "off" 
 
     }] 
 
    }] 
 
    } 
 
} 
 

 

 
var numMods = Object.keys(json.productDetails.productModifiers[0]).length; 
 
console.log("There are " + numMods + " categories of modifiers.");

來源

2017-02-15 04:07:31 matt

這對於獲取節點數量非常有用。這就是說 - 我怎麼能訪問實際的節點名稱？（即：面，面，面，麪包）。 –

@JohnHubler Object.keys（json.productDetails.productModifiers [0]）將包含節點名稱。只需在獲取其長度之前將其保存到變量:) – matt

我猜即使你的productModifiers擁有一個數組;該數組只保存4個鍵的單個對象。能否請您用下面的代碼試試：

var data = { 
 
    "productDetails": { 
 
    "productThumb": "/uploads/[email protected]/showup-bg4.jpg", 
 
    "productName": "Hamburger", 
 
    "productDesc": "Made with 100% American ground beef", 
 
    "productPrice": "9.99", 
 
    "productModifiers": [{ 
 
     "Sides": [{ 
 
     "modifierName": "Applesauce", 
 
     "modifierUpcharge": "0", 
 
     "isDefault": "off" 
 
     }, { 
 
     "modifierName": "Rice", 
 
     "modifierUpcharge": "0", 
 
     "isDefault": "off" 
 
     }], 
 
     "Toppings": [{ 
 
     "modifierName": "Bacon", 
 
     "modifierUpcharge": "0.25", 
 
     "isDefault": "off" 
 
     }, { 
 
     "modifierName": "Tomato", 
 
     "modifierUpcharge": "0", 
 
     "isDefault": "on" 
 
     }], 
 
     "Doneness": [{ 
 
     "modifierName": "Extra Well", 
 
     "modifierUpcharge": "0", 
 
     "isDefault": "off" 
 
     }, { 
 
     "modifierName": "Well", 
 
     "modifierUpcharge": "0", 
 
     "isDefault": "off" 
 
     }], 
 
     "Breads": [{ 
 
     "modifierName": "White Bun", 
 
     "modifierUpcharge": "0", 
 
     "isDefault": "on" 
 
     }, { 
 
     "modifierName": "Whole Wheat Bun", 
 
     "modifierUpcharge": "0", 
 
     "isDefault": "off" 
 
     }] 
 
    }] 
 
    } 
 
}; 
 

 
var productModifiersObj = data.productDetails.productModifiers[0]; 
 

 
var count = 0; 
 
var i; 
 

 
for (i in productModifiersObj) { 
 

 
    if (productModifiersObj.hasOwnProperty(i)) { 
 
    count++; 
 
    } 
 
} 
 

 
alert("There are " + count + " categories of modifiers.");

來源

2017-02-15 04:07:00 vijayP

而是然後循環。查看我的答案，獲取Object.keys然後獲取返回列表的長度會更容易，更高效。 :) – matt

Object.keys'在大多數現代瀏覽器上都能正常工作，儘管它與舊版IE瀏覽器不兼容...所以它最好使用通用兼容代碼。 – vijayP

很高興知道，相當真實。 – matt

計數JSON節點不工作

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