比較2個陣列，下劃線的對象找到differnce

我有2個陣列，一個是的newval，另一個是origVal定義比較2個陣列，下劃線的對象找到differnce

原稿：

[ 
{"ListingId":1762276,"Rating":3,"ListPrice":7411828,"PropertyType":"Residential"}, 
{"ListingId":1826692,"Rating":3,"ListPrice":650000,"PropertyType":"Residential"}, 
{"ListingId":1833283,"Rating":4,"ListPrice":950000,"PropertyType":"Residential"}, 
{"ListingId":1832134,"Rating":3,"ListPrice":850000,"PropertyType":"Residential"}, 
{"ListingId":1829932,"Rating":4,"ListPrice":750000,"PropertyType":"Residential"}, 
{"ListingId":1827548,"Rating":5,"ListPrice":650000,"PropertyType":"Residential"} 
]

新：

[ 
{"ListingId":1762276,"Rating":2,"ListPrice":7411828,"PropertyType":"Residential"}, 
{"ListingId":1826692,"Rating":3,"ListPrice":650000,"PropertyType":"Residential"}, 
{"ListingId":1833283,"Rating":4,"ListPrice":950000,"PropertyType":"Residential"}, 
{"ListingId":1832134,"Rating":3,"ListPrice":850000,"PropertyType":"Residential"}, 
{"ListingId":1829932,"Rating":4,"ListPrice":750000,"PropertyType":"Residential"}, 
{"ListingId":1827548,"Rating":5,"ListPrice":650000,"PropertyType":"Residential"} 
]

如果我更改新的評分之一，我如何檢測該更改並檢索更改的對象？

一次只會有一個變化，但我認爲不重要。

FYI：這些陣列正在從一個Anjularjs watchcollection

$scope.$watchCollection('items', function (new, old) { 

}, true);

生產謝謝斯蒂芬

來源

2013-08-22 Stephen Patten

是那些陣列（即''===身份）在同一個對象還是僅僅是相似的外觀？ – Bergi

你需要什麼結果？數組中已更改對象的索引，新更改對象，舊更改對象，評級？ – Bergi

我更喜歡改變的對象ie {「ListingId」：1762276，「Rating」：2，「ListPrice」：7411828，「PropertyType」：「Residential」} –

看看這個：

var a = [ 
{"ListingId":1762276,"Rating":3,"ListPrice":7411828,"PropertyType":"Residential"}, 
{"ListingId":1826692,"Rating":3,"ListPrice":650000,"PropertyType":"Residential"}, 
{"ListingId":1833283,"Rating":4,"ListPrice":950000,"PropertyType":"Residential"}, 
{"ListingId":1832134,"Rating":3,"ListPrice":850000,"PropertyType":"Residential"}, 
{"ListingId":1829932,"Rating":4,"ListPrice":750000,"PropertyType":"Residential"}, 
{"ListingId":1827548,"Rating":5,"ListPrice":650000,"PropertyType":"Residential"} 
]; 

var b = [ 
{"ListingId":1762276,"Rating":2,"ListPrice":7411828,"PropertyType":"Residential"}, 
{"ListingId":1826692,"Rating":3,"ListPrice":650000,"PropertyType":"Residential"}, 
{"ListingId":1833283,"Rating":4,"ListPrice":950000,"PropertyType":"Residential"}, 
{"ListingId":1832134,"Rating":3,"ListPrice":850000,"PropertyType":"Residential"}, 
{"ListingId":1829932,"Rating":4,"ListPrice":750000,"PropertyType":"Residential"}, 
{"ListingId":1827548,"Rating":5,"ListPrice":650000,"PropertyType":"Residential"} 
] 

var difference = function(array){ 
    var rest = Array.prototype.concat.apply(Array.prototype, Array.prototype.slice.call(arguments, 1)); 

    var containsEquals = function(obj, target) { 
    if (obj == null) return false; 
    return _.any(obj, function(value) { 
     return _.isEqual(value, target); 
    }); 
    }; 

    return _.filter(array, function(value){ return ! containsEquals(rest, value); }); 
}; 

console.log(JSON.stringify(difference(b, a))); 
> [{"ListingId":1762276,"Rating":2,"ListPrice":7411828,"PropertyType":"Residential"}]

的代碼是基於原有的功能difference從底線，但執行使用isEqual對象之間有很深的比較。

來源

2013-08-22 15:01:16

並感謝您使用JSON.stringify的調試技巧 –

，它能做什麼。我希望我能理解代碼。 – mcktimo

如果訂單沒有變化，一個簡單的迭代將做到這一點。下劃線提供find method此任務：

var changedObj = _.find(newVal, function(obj, index) { 
    return obj.Rating != oldVal[index].Rating; 
});

來源

2013-08-22 14:54:54 Bergi

如何：

const current = [{name:'a'},{name:'b'},{name:'c'}] 
const update = [{name:'x'},{name:'a'},{name:'b'},{name:'f'}] 
const records = current.concat(update); 
const diff = {}; 
diff.in = [] 
diff.out = []; 
records.forEach(item => { 
    if(!current.find(cur => item.name == cur.name))diff.in.push(item) 
    if(!update.find(up => item.name == up.name))diff.out.push(item) 
})

來源

2016-12-18 04:17:11 thecommoner

比較2個陣列，下劃線的對象找到differnce

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