如何在javascript中从现有数组创建一个新数组

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【中文标题】如何在javascript中从现有数组创建一个新数组【英文标题】：how to create a new array from existing array in javascript 【发布时间】：2018-08-09 03:00:26 【问题描述】：

我是 javascript 的新手，我必须过滤一个数组，所以我用谷歌搜索，并花时间寻找解决方案，但没有人帮助我。PLZ 帮助我。 我有以下数组，它是查询的结果：

"clause": [
    
        "clause_id": 1,
        "clause_text": "A",
        "clause_item_id": 1,
        "item_text": "this text is related to clause 1 ",
        "item_photo": ""
    ,
    
        "clause_id": 2,
        "clause_text": "B",
        "clause_item_id": 2,
        "item_text": "this text is related to clause 2 ",
        "item_photo": ""
    ,
    
        "clause_id": 2,
        "clause_text": "B",
        "clause_item_id": 3,
        "item_text": "this text is related to clause 2",
        "item_photo": ""
    ,
    
        "clause_id": 2,
        "clause_text": "B",
        "clause_item_id": 4,
        "item_text": "this text is related to clause 2",
        "item_photo": ""
    ,
    
        "clause_id": 3,
        "clause_text": "C",
        "clause_item_id": 5,
        "item_text": "this text is related to clause 3",
        "item_photo": ""
    ,
    
        "clause_id": 3,
        "clause_text": "C",
        "clause_item_id": 6,
        "item_text": "this text is related to clause 3",
        "item_photo": ""
    ,
    
        "clause_id": 3,
        "clause_text": "C",
        "clause_item_id": 7,
        "item_text": "this text is related to clause 3",
        "item_photo": ""
    
]

我想改变它的格式。并将其作为 JSON 响应发送给客户端。所以上面的数组应该被重复多次的子句 id 过滤。我想重新格式化数组并避免重复某些数组元素。所以我想要的最终数组是这样的：

        "clauses": [
    
        "cls": 
            "clause_id": 1,
            "clause_text": "A"
        ,
        "items": [
            
                "claud_item_id": 1,
                "item_text": "this text is related to clause 1",
                "item_photo": ""
            
        ]
    ,
    
        "cls": 
            "clause_id": 2,
            "clause_text": "B"
        ,
        "items": [
            
                "claud_item_id": 2,
                "item_text": "this text is related to clause 2",
                "item_photo": ""
            ,
            
                "claud_item_id": 3,
                "item_text": "this text is related to clause 2",
                "item_photo": ""
            ,
            
                "claud_item_id": 4,
                "item_text": "this text is related to clause 2",
                "item_photo": ""
            
        ]
    ,
    
        "cls": 
            "clause_id": 3,
            "clause_text": "C"
        ,
        "items": [
            
                "claud_item_id": 5,
                "item_text": "this text is related to clause 3",
                "item_photo": ""
            ,
            
                "claud_item_id": 6,
                "item_text": "this text is related to clause 3",
                "item_photo": ""
            ,
            
                "claud_item_id": 7,
                "item_text": "this text is related to clause 3",
                "item_photo": ""
            
        ]
    
]

请帮帮我

【问题讨论】：

标题提到了过滤——误导，你想转换数据——无论哪种情况，SO都不是代码编写服务——你试过什么 请使用谷歌获得初步帮助。然后尝试实现一些东西，如果你被困在某个地方或者你想要替代品，请分享你的尝试，我们会帮助你 顺便说一句，你需要的格式是不可能你不能在一个对象中有多个同名的键......你可能想要items成为一个对象数组 【参考方案1】：

因此，您可以构建一个新的 javascript 对象，但如果您在同一个对象中重复了“项目”的对象属性，这可能会很棘手。我通过使结果具有这样的项目数组来解决此问题。

该算法使用双 for 循环，因此对于大 json 大小会很昂贵，但它有效。

这是假设要排序的 json 对象名为“obj”的代码和输出。

var newObj = "clause":[];
var i,j;
for(i = 0; i < obj.clause.length; i++)
  var current = obj.clause[i];
  for(j = 0; j < newObj.clause.length; j++)
    if(newObj.clause[j].cls && newObj.clause[j].cls["clause_id"] == current["clause_id"])
      var subObj = "claud_item_id": current["clause_item_id"], "item_text": current["item_text"], "item_photo": current["item_photo"];    
      newObj.clause[j].items.push(subObj);
      break;
    
  
  if(j == newObj.clause.length)
    var subObj = "cls": "clause_id": current["clause_id"], "clause_text": current["clause_text"], 
                  "items": ["claud_item_id": current["clause_item_id"], "item_text": current["item_text"], "item_photo": current["item_photo"]];     
    newObj.clause.push(subObj);

这是 newObj 的值。


"clause": [
    "cls": 
        "clause_id": 1,
        "clause_text": "A"
    ,
    "items": [
        "claud_item_id": 1,
        "item_text": "this text is related to clause 1 ",
        "item_photo": ""
    ]
, 
    "cls": 
        "clause_id": 2,
        "clause_text": "B"
    ,
    "items": [
        "claud_item_id": 2,
        "item_text": "this text is related to clause 2 ",
        "item_photo": ""
    , 
        "claud_item_id": 3,
        "item_text": "this text is related to clause 2",
        "item_photo": ""
    , 
        "claud_item_id": 4,
        "item_text": "this text is related to clause 2",
        "item_photo": ""
    ]
, 
    "cls": 
        "clause_id": 3,
        "clause_text": "C"
    ,
    "items": [
        "claud_item_id": 5,
        "item_text": "this text is related to clause 3",
        "item_photo": ""
    , 
        "claud_item_id": 6,
        "item_text": "this text is related to clause 3",
        "item_photo": ""
    , 
        "claud_item_id": 7,
        "item_text": "this text is related to clause 3",
        "item_photo": ""
    ]
]

【讨论】：

谢谢，它对我有用，这正是我想要的。 @约翰【参考方案2】： 

var item_val = item_val = "clause": [
    
        "clause_id": 1,
        "clause_text": "A",
        "clause_item_id": 1,
        "item_text": "this text is related to clause 1 ",
        "item_photo": ""
    ,
    
        "clause_id": 2,
        "clause_text": "B",
        "clause_item_id": 2,
        "item_text": "this text is related to clause 2 ",
        "item_photo": ""
    ,
    
        "clause_id": 2,
        "clause_text": "B",
        "clause_item_id": 3,
        "item_text": "this text is related to clause 2",
        "item_photo": ""
    ,
    
        "clause_id": 2,
        "clause_text": "B",
        "clause_item_id": 4,
        "item_text": "this text is related to clause 2",
        "item_photo": ""
    ,
    
        "clause_id": 3,
        "clause_text": "C",
        "clause_item_id": 5,
        "item_text": "this text is related to clause 3",
        "item_photo": ""
    ,
    
        "clause_id": 3,
        "clause_text": "C",
        "clause_item_id": 6,
        "item_text": "this text is related to clause 3",
        "item_photo": ""
    ,
    
        "clause_id": 3,
        "clause_text": "C",
        "clause_item_id": 7,
        "item_text": "this text is related to clause 3",
        "item_photo": ""
    
]

var result_val  = ;
       item_val['clause'].forEach(function(val)
                var t   = 'item_photo': val['item_photo'],'item_text':val['item_text'],'clause_item_id':val['clause_item_id']
                if(!(val['clause_id'] in result_val))           
                        result_val[val['clause_id']]    =     
                if(!(val['clause_text'] in result_val[val['clause_id']]))
                        result_val[val['clause_id']][val['clause_text']] =  
                if('item' in result_val[val['clause_id']][val['clause_text']])
                        result_val[val['clause_id']][val['clause_text']]['item'].push(t)
                else
                        result_val[val['clause_id']][val['clause_text']]['item']        = []
                        result_val[val['clause_id']][val['clause_text']]['item'].push(t)
                
                
        )
console.log(result_val)

【讨论】：

无法在 Object 中使用相同的多个键（因此您的例外不可能）。您可以使用这种替代解决方案

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