Javascript 如何在嵌套的 JSON 中导航
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How to navigate in nested JSON
提问by Denis
I have nested JSON object like
我嵌套了 JSON 对象，例如
{"baseball":
{"mlb":
{"regular":
{"_events": [{"start_time": "2011-07-31 17:35", "lines":
[{"comment": "", "coeff": "2.35", "title": "2", "old_coeff": "2.35", "is_main": true},
{"comment": "", "coeff": "1.59", "title": "2", "old_coeff": "1.59", "is_main": true},
{"comment": "", "coeff": "1.59", "title": "2", "old_coeff": "1.59", "is_main": true},
{"comment": "", "coeff": "2.35", "title": "2", "old_coeff": "2.35", "is_main": true}],
"members": ["atlanta", "florida"]
}
]
}}}}
And i need get _events array and parse it too. But I don't know what will be in cells before _events and how they will. How do I work with this structure?
我需要获取 _events 数组并解析它。但我不知道在 _events 之前单元格中会有什么以及它们如何。我如何使用这种结构？
回答by Gabi Purcaru
function recursiveGetProperty(obj, lookup, callback) {
for (property in obj) {
if (property == lookup) {
callback(obj[property]);
} else if (obj[property] instanceof Object) {
recursiveGetProperty(obj[property], lookup, callback);
}
}
}
And just use it like this:
就像这样使用它：
recursiveGetProperty(yourObject, '_events', function(obj) {
// do something with it.
});
Here's a working jsFiddle: http://jsfiddle.net/ErHng/(note: it outputs to the console, so you need to Ctrl+Shift+J/Cmnd+Option+Iin chrome or open firebug in Firefox and then re-run it)
这是一个有效的 jsFiddle：http: //jsfiddle.net/ErHng/（注意：它输出到控制台，所以你需要在 chrome 中Ctrl+Shift+J/Cmnd+Option+I或在 Firefox 中打开 firebug 然后重新运行它）
回答by cwallenpoole
If the structure is known:
如果结构已知：
Assuming that you have the above in a String called input (and that the JSON is valid):
假设您在名为 input 的字符串中有上述内容（并且 JSON 有效）：
var obj = JSON.parse(input) // converts it to a JS native object.
// you can descend into the new object this way:
var obj.baseball.mlb.regular._events
As a warning, earlier versions of IE do not have JSON.parse, so you will need to use a framework for that.
作为警告，早期版本的 IE 没有 JSON.parse，因此您需要为此使用框架。
If the structure is unknown:
如果结构未知：
// find the _events key
var tmp = input.substr(input.indexOf("_events"))
// grab the maximum array contents.
tmp = tmp.substring( tmp.indexOf( "[" ), tmp.indexOf( "]" ) + 1 );
// now we have to search the array
var len = tmp.length;
var count = 0;
for( var i = 0; i < len; i++ )
{
var chr = tmp.charAt(i)
// every time an array opens, increment
if( chr == '[' ) count++;
// every time one closes decrement
else if( chr == ']' ) count--;
// if all arrays are closed, you have a complete set
if( count == 0 ) break;
}
var events = JSON.parse( tmp.substr( 0, i + 1 ) );
回答by stef
The easiest thing to do in this situation, I find, is to go to JSFiddle, paste in your json as a variable:
我发现在这种情况下，最简单的方法是转到JSFiddle，将您的 json 作为变量粘贴：
var json = {"baseball": ... etc.
console.log(json);
Then using Chrome, "View" -> "Developer" -> "Javascript console" start to experiment with what the data structure looks like in order to build up your parsing function.
然后使用 Chrome，“查看”->“开发人员”->“Javascript 控制台”开始尝试数据结构的外观，以构建您的解析功能。
Then start experimenting with the structure. Eg.
然后开始尝试结构。例如。
console.log(json.baseball.mlb.regular._events);
Or if you turn on JQuery:
或者，如果您打开 JQuery：
$.each(json.baseball.mlb.regular._events, function(i, item){
$.each(item.lines,function(i,line){
console.log(line.coeff);
});
});
If you're having trouble actually loading in this JSON into a variable you'll need to JSON.parse a string retrieved via an AJAX call I suspect.
如果您在实际将此 JSON 加载到变量中时遇到问题，您需要对通过我怀疑的 AJAX 调用检索的字符串进行 JSON.parse。
回答by Prashant Dubey
I was looking for similar issues I found a library JsonQ which is best to do these stuffs and update keys an all.believe me I found it very helpful
我正在寻找类似的问题，我发现了一个库 JsonQ，它最适合做这些事情并更新密钥。相信我，我发现它非常有帮助
