Question

我在操纵List<Dictionary<string,string>>> SSRList以便轻松获取数据方面遇到麻烦。我已经走了这么远：

var bleh = SSRList
    .Where(x => x.ContainsKey("ServiceTechHrs"))  //Scott Shauf total tech hours
    .Where(x => x.ContainsKey("ServiceTech") && x.ContainsValue("Scott Shauf"))
    .Select(x => x["ServiceTechHrs"])
    .Where(x => x != "")
    .Sum(x => Convert.ToDouble(x))
    .Dump("All Scott Shauf TechNumbers");

这回答了斯科特作为技术员总共工作了多少小时。

我将如何回答“斯科特和道格担任技术员或工程师花费了几个小时？”我在语法上遇到了麻烦，可以让我询问lambda表达式...同样，我想知道如何在Dict Keys上执行“ GroupBy”？

Answer 1

正如其他人指出的那样，使用Dictionary<string, string>表示某种结构化类型会使您摆脱LINQ的全部魅力。但是，如果由于某些（可疑的）设计原因而不得不走这条路，那么尽快进行强类型输入将使它返回。

您似乎想使用类似的东西

public interface ITechnician
{
    string ServiceTech { get; }
    double ServiceTechHours { get; } // or should it be TimeSpan?
}

我会写一些代码来完成肮脏的工作：

public static class MyExtensions
{
    public static IEnumerable<ITechnician> OfTypeTechnician(this IEnumerable<IDictionary<string, string>> records)
    {
        foreach (var record in records)
        {
            if (!record.TryGetValue("ServiceTech", out var serviceTech)) continue;
            if (!record.TryGetValue("ServiceTechHrs", out var serviceTechHrsStr) || !double.TryParse(serviceTechHrsStr, out var serviceTechHrs)) continue;
            yield return new Technician { ServiceTech = serviceTech, ServiceTechHours = serviceTechHrs };
        }
    }

    private class Technician : ITechnician
    {
        public string ServiceTech { get; set; }
        public double ServiceTechHours { get; set; }
    }
}

休息很简单：

var records = new[]
{
    new Dictionary<string, string> { { "ServiceTech", "Scott Shouf"}, { "ServiceTechHrs", "4711" } },
    new Dictionary<string, string> { { "ServiceTech", "Scott Shouf"}, { "ServiceTechHrs", "0815" } },
    new Dictionary<string, string> { { "ServiceTech", "Scott Shouf"}, { "ServiceTechHrs", "not convertible to double" } },
    new Dictionary<string, string> { { "ServiceTech", "Someone Else"}, { "ServiceTechHrs", "42" } },
    new Dictionary<string, string> { { "Animal", "Giraffe" } }
};

var allScottShaufTechNumbers = records
    .OfTypeTechnician()
    .Where(t => t.ServiceTech == "Scott Shouf")
    .Sum(t => t.ServiceTechHours);
// 5526

如何从List <dictionary <string，string =“”>

1 个答案: