Javascript 使用正则表达式搜索嵌套对象答案

【问题标题】：Javascript Search Nested Object with RegexJavascript 使用正则表达式搜索嵌套对象
【发布时间】：2015-08-31 16:45:09
【问题描述】：

我有这个：

var foo = {
          "Category1": [
            {"Company1": {"URL": ["DomainName1", "DomainName2"]}},
            ...
          ],
          ...
          }

通常，我会像这样访问 DomainName1：

foo["Category1"][0]["Company1"]["URL"][0]

但是，我想在所有foo 中搜索某个域名，但我不知道任何其他信息。我知道我可以使用多个嵌套的 for 循环，但这非常非常很慢。什么是有效的方法来做到这一点？我在想一些类似于'*' 代替["Category1"]、[0] 等的东西，但我不知道该怎么做。

任何帮助将不胜感激。

【问题讨论】：

您的foo 对象有多大？树是固定结构还是嵌套层数可以非常多？您究竟在搜索什么：URL 值或foo 中的“地址”？ 非常非常慢是什么意思？希望它有多快？从你的话我想你还没有尝试过递归解决方案......
那么你想要什么，对类别、公司或网址的引用？
您可能想要重组数据，以便搜索变得更加高效。例如。 [[url, [company, ...], ...]（已排序）并执行二分查找。
我认为编写正则表达式将是一项艰巨的任务，并且可能不会比循环表现更好
正如 Felix 所说，如果数据变化不大，最好建立一个索引并使用它。我会使用如下对象：{url1: [company1, company2], url2: [comany3, company4],...} 其中 company 是对相关公司对象的引用或作为字符串的名称，无论适合什么。

标签： javascript regex json object nested

【解决方案1】：

我的回答可能是固执己见，但仍然...使用数万个对象，您正试图重新发明轮子。这是数据库存储的确切候选者。 SQL 或非 SQL，如 MongoDB。

【讨论】：

【解决方案2】：

用Jsonpath解决这个问题很好。

例如，您可以使用此表达式来查找所有 URL：

var out = jsonPath(json, "$..URL[*]").toJSONString() + "\n";
document.write(out);

您可以使用表达式来匹配您想要的域。

对于您的情况，您可以使用以下表达式：

$..URL[?(@.indexOf('DomainName1') != -1)]

Jsonpath online tool

这是一个来自 documentation 的有用 Jsonpath 示例：

<html>
<head>
<title> JSONPath - Example (js)</title>
<script type="text/javascript" src="json.js"></script>
<script type="text/javascript" src="jsonpath.js"></script>
</head>
<body>
<pre>
<script type="text/javascript">
   var json = 
                  { "store": {
                        "book": [ 
                          { "category": "reference",
                                "author": "Nigel Rees",
                                "title": "Sayings of the Century",
                                "price": 8.95
                          },
                          { "category": "fiction",
                                "author": "Evelyn Waugh",
                                "title": "Sword of Honour",
                                "price": 12.99
                          },
                          { "category": "fiction",
                                "author": "Herman Melville",
                                "title": "Moby Dick",
                                "isbn": "0-553-21311-3",
                                "price": 8.99
                          },
                          { "category": "fiction",
                                "author": "J. R. R. Tolkien",
                                "title": "The Lord of the Rings",
                                "isbn": "0-395-19395-8",
                                "price": 22.99
                          }
                        ],
                        "bicycle": {
                          "color": "red",
                          "price": 19.95
                        }
                  }
                },
           out = "";
       out += jsonPath(json, "$.store.book[*].author").toJSONString() + "\n>";
       out += jsonPath(json, "$..author").toJSONString() + "\n";
       out += jsonPath(json, "$.store.*").toJSONString() + "\n";
       out += jsonPath(json, "$.store..price").toJSONString() + "\n";
       out += jsonPath(json, "$..book[(@.length-1)]").toJSONString() + "\n";
       out += jsonPath(json, "$..book[-1:]").toJSONString() + "\n";
       out += jsonPath(json, "$..book[0,1]").toJSONString() + "\n";
       out += jsonPath(json, "$..book[:2]").toJSONString() + "\n";
       out += jsonPath(json, "$..book[?(@.isbn)]").toJSONString() + "\n";
       out += jsonPath(json, "$..book[?(@.price<10)]").toJSONString() + "\n";
       out += jsonPath(json, "$..*").toJSONString() + "\n";
       document.write(out);
  </script>
</pre>
</body>
</html>

示例输出：

["Nigel Rees","Evelyn Waugh","Herman Melville","J. R. R. Tolkien"]
["Nigel Rees","Evelyn Waugh","Herman Melville","J. R. R. Tolkien"]
[[{"category":"reference","author":"Nigel Rees","title":"Sayings of the Century","price":8.95},{"category":"fiction","author":"Evelyn Waugh","title":"Sword of Honour","price":12.99},{"category":"fiction","author":"Herman Melville","title":"Moby Dick","isbn":"0-553-21311-3","price":8.99},{"category":"fiction","author":"J. R. R. Tolkien","title":"The Lord of the Rings","isbn":"0-395-19395-8","price":22.99}],{"color":"red","price":19.95}]
[8.95,12.99,8.99,22.99,19.95]
[{"category":"fiction","author":"J. R. R. Tolkien","title":"The Lord of the Rings","isbn":"0-395-19395-8","price":22.99}]
[{"category":"fiction","author":"J. R. R. Tolkien","title":"The Lord of the Rings","isbn":"0-395-19395-8","price":22.99}]
[{"category":"reference","author":"Nigel Rees","title":"Sayings of the Century","price":8.95},{"category":"fiction","author":"Evelyn Waugh","title":"Sword of Honour","price":12.99}]
[{"category":"reference","author":"Nigel Rees","title":"Sayings of the Century","price":8.95},{"category":"fiction","author":"Evelyn Waugh","title":"Sword of Honour","price":12.99}]
[{"category":"fiction","author":"Herman Melville","title":"Moby Dick","isbn":"0-553-21311-3","price":8.99},{"category":"fiction","author":"J. R. R. Tolkien","title":"The Lord of the Rings","isbn":"0-395-19395-8","price":22.99}]
[{"category":"reference","author":"Nigel Rees","title":"Sayings of the Century","price":8.95},{"category":"fiction","author":"Herman Melville","title":"Moby Dick","isbn":"0-553-21311-3","price":8.99}]
[{"book":[{"category":"reference","author":"Nigel Rees","title":"Sayings of the Century","price":8.95},{"category":"fiction","author":"Evelyn Waugh","title":"Sword of Honour","price":12.99},{"category":"fiction","author":"Herman Melville","title":"Moby Dick","isbn":"0-553-21311-3","price":8.99},{"category":"fiction","author":"J. R. R. Tolkien","title":"The Lord of the Rings","isbn":"0-395-19395-8","price":22.99}],"bicycle":{"color":"red","price":19.95}},[{"category":"reference","author":"Nigel Rees","title":"Sayings of the Century","price":8.95},{"category":"fiction","author":"Evelyn Waugh","title":"Sword of Honour","price":12.99},{"category":"fiction","author":"Herman Melville","title":"Moby Dick","isbn":"0-553-21311-3","price":8.99},{"category":"fiction","author":"J. R. R. Tolkien","title":"The Lord of the Rings","isbn":"0-395-19395-8","price":22.99}],{"color":"red","price":19.95},{"category":"reference","author":"Nigel Rees","title":"Sayings of the Century","price":8.95},{"category":"fiction","author":"Evelyn Waugh","title":"Sword of Honour","price":12.99},{"category":"fiction","author":"Herman Melville","title":"Moby Dick","isbn":"0-553-21311-3","price":8.99},{"category":"fiction","author":"J. R. R. Tolkien","title":"The Lord of the Rings","isbn":"0-395-19395-8","price":22.99},"reference","Nigel Rees","Sayings of the Century",8.95,"fiction","Evelyn Waugh","Sword of Honour",12.99,"fiction","Herman Melville","Moby Dick","0-553-21311-3",8.99,"fiction","J. R. R. Tolkien","The Lord of the Rings","0-395-19395-8",22.99,"red",19.95]

只需使用您想要的表达式即可轻松查询您的 json 结构。

【讨论】：

我想知道这会比直接使用纯 javascript 迭代属性更快...
@KirillSlatin jsonpath 是过滤大型 json 的工具，既然已经有工具可以帮助处理 json 查询，为什么还要重新发明轮子……
所有+= 都会非常慢。
问题不在于+=... 正则表达式解析会产生开销，这是肯定的。而且没有算法改进，只是语法糖。