获取 JSON 文件中的前 10 个值 [重复]

Posted 2023-03-27

【中文标题】获取 JSON 文件中的前 10 个值 [重复]

【英文标题】：Getting top 10 Values in a JSON File [duplicate]

【发布时间】：2015-02-13 07:05:33

【问题描述】：

这是我的 JSON 文件的示例。

[
    "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
]

我怎样才能只获得从变量 1 数字最高到最少的前 10 个？但是会以相同的格式传递 JSON 文件。

【参考方案1】：

首先，将 JSON 解析为 Objects 数组：

var data = JSON.parse(json);

然后结合sort和slice来实现你的目标：

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

见Array.sort

【讨论】：

比较中有错字。应该是a.Variable1 > b.Variable1

不，拥有a.Variable1 > b.Variable1 将显示生成数组并显示最低值。旧帖子，但可能对想要节省一分钟的人有所帮助。

【参考方案2】：

您可以使用Alasql javascript 库来实现。它下载 json 文件，解析它，然后运行 SQL 语句就可以了。这是一个如何直接从 JSON 文件中获取前 10 名的示例：

<script src="alasql.min.js></script>
<script>
    alasql("SELECT TOP 10 * FROM JSON('mydata.json') ORDER BY Variable1 DESC",[], function(top10)
        console.log(top10);
    );
</script>

或者如果你已经在内存中有数据：

    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this sample。

【讨论】：

有什么办法可以用php实现这个吗？？

不错的图书馆，感谢分享