关于javascript：获取JSON文件中的前10个值


Getting top 10 Values in a JSON File

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这是我的JSON文件的一个例子。

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[
    {"Variable":"Hello","Variable1":20}, {"Variable":"Hi","Variable1":30},
    {"Variable":"How","Variable1":40}, {"Variable":"Who","Variable1":50},
    {"Variable":"Where","Variable1":60}, {"Variable":"This","Variable1":100},
    {"Variable":"Pork","Variable1":10}, {"Variable":"Creep","Variable1":90},
    {"Variable":"Mega Creeps","Variable1":80}, {"Variable":"LOL","Variable1":0},
    {"Variable":"ROFL","Variable1":0}, {"Variable":"LMAO","Variable1":0},
    {"Variable":"POP","Variable1":0}, {"Variable":"LOVE","Variable1":0},
    {"Variable":"PICK","Variable1":0}, {"Variable":"WHIZ","Variable1":0},
    {"Variable":"BORED","Variable1":0}, {"Variable":"KILLAH","Variable1":0},
    {"Variable":"LOLLING","Variable1":0}, {"Variable":"HALOO  HALOO","Variable1":0}
]

我怎样才能从最高的变量1中得到前10个？但将以相同的格式传递JSON文件。

首先，将JSON解析为一个对象数组：

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var data = JSON.parse(json);

然后结合sort和slice实现您的目标：

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var top10 = data.sort(function(a, b) { return a.Variable1 < b.Variable1 ? 1 : -1; })
                .slice(0, 10);

号

请参见array.sort

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您可以使用alasql javascript库来完成这项工作。它下载JSON文件，解析它，然后运行上面的SQL语句。下面是如何直接从JSON文件中获取前10个示例：

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<script src="alasql.min.js>

    alasql("SELECT TOP 10 * FROM JSON('mydata.json') ORDER BY Variable1 DESC",[], function(top10){
        console.log(top10);
    });

或者，如果内存中已经有数据：

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    var data = [{"Variable":"Hello","Variable1":20},{"Variable":"Hi","Variable1":30}];
    var res = alasql("SELECT TOP 10 * FROM ? ORDER BY Variable1 DESC",[data]);

。

在jsFiddle中尝试此示例。

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