如何在vb.net中总结结构数组的相似元素? [英] How to sum similar element of an array of structure in vb.net?

问题描述

我有一个结构数组:

Public Structure emp
    Public empName As String
    Public empAge As Int32
    Public empsal As Int32 ' salary
End Structure

具有 30 个元素的上述结构的数组.我想对 emp.empName & 的那些 emp 元素的 empsal 求和emp.empAge 是相等的.

An array of the above structure with 30 element. I want to sum the empsal of those emp elements whose emp.empName & emp.empAge is equal.

例如

emp(0).empName = "test"
emp(0).empAge = 32
emp(0).empsal = 10000

emp(1).empName = "test"
emp(1).empAge = 32
emp(1).empsal = 10000

emp(2).empName = "test12"
emp(2).empAge = 32
emp(2).empsal = 10000

如何才能使结果为 (test,20000) 和 (test12,10000)?

使用 .NET 3.5

Using .NET 3.5

推荐答案

编辑样本以在键中包含年龄，并以 emp 数组结束.

Edited the samples to include the age in the key, and to end up with an emp array.

绝对的.为此，您应该查看 LINQ - 您基本上希望按姓名和年龄分组，然后求和工资.在 C# 中，您可以编写如下代码:

Absolutely. You should look at LINQ for this - you basically want to group by name and age, and then sum the salary. In C# you'd write something like:

var query = employees.GroupBy
     (x => new { x.empName, x.empAge },
      x => x.empSal,
      (key, salaries) => new emp { empName = key.empName,
                                   empAge = key.empAge,
                                   empSalary = salaries.Sum() })
var array = query.ToArray();

我认为在 VB 中应该是这样的:

I think in VB this would be something like:

Dim query = employees.GroupBy( _
    Function(x) New With { Key .Name = x.empName, Key .Age = x.empAge }, _
    Function(x) x.empSal, _
    Function(k, salaries) New Emp With _
         { .empName = k.Name, .empAge = k.Age, .empSalary = salaries.Sum() }_
    )
Dim array = query.ToArray()

请参阅 GroupBy 文档 了解更多详情.

See the GroupBy documentation for more details.

顺便说一句，我建议:

• 根据 .NET 命名约定为您的类型提供更完整的名称
• 使它成为一个类而不是一个结构(它不是一个真正的单一值，如 int)
• 使用属性代替公共字段
• 从字段/属性中删除 emp 前缀 - 毕竟它们已经是员工类型的一部分

• Giving your type a fuller name which follows .NET naming conventions
• Making it a class rather than a structure (it's not really a single value, like an int)
• Using properties instead of public fields
• Removing the emp prefix from the fields/properties - they're already part of an employee type, after all

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