linqjs group with a sum [英] linqjs group by with a sum

问题描述

这似乎是一个简单的问题，但我正在努力使用linqjs语法。

This might seems like an easy question but I'm struggling with the linqjs syntax.

给出以下基本JSON：

Given the following basic JSON:

{
        "DateEvent": "2013-04-23 14:00:00Z",
        "DateRecord": "2013-04-23 14:00:00Z",
        "Amount": -9500,
        "Type": {
            "Description": "Capital"
        },
        "Currency": {
            "ID": "USD",
        }
}

使用linqjs如何返回每种货币的总额？

Using linqjs how can I return the total for each currency?

Enumerable.From(data)
    .GroupBy("{ currency: $.Currency.ID }", null, 
        function (key, g) {
            var result = {
                    currency: key.currency,
                    total: g.Sum($.Amount)
                }});

上面的代码不起作用。

推荐答案

你几乎拥有它。 GroupBy和Sum中的键选择器不正确。键选择器也需要是一个字符串。请尝试以下操作：

You almost had it. Your key selector in your GroupBy and Sum is incorrect. Also the key selector needs to be a string. Try the following:

var result = Enumerable.From(data).GroupBy("$.Currency.ID", null,
    function (key, g) {
        var result = {
            currency: key,
            total: g.Sum("$.Amount")
        }
        return result;
    }).ToArray();

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