LINQ |如何找到给定序列的总和？

在LINQ中，可以使用Sum()方法找到给定数字元素的总和。此方法计算给定序列中存在的数值的总和。它在C＃中不支持查询语法，但是在VB.NET中支持。它在C＃中的Enumerable和Queryable类中均可用。它可以与可为空，不可为空的十进制，双精度，浮点数，整数等值一起使用。

范例1：

// C# program to illustrate how to
// find the sum of the given sequence
using System;
using System.Linq;
  
class GFG {
  
    // Main Method
    static public void Main()
    {
  
        int[] sequence = { 20, 30, 50, 78, 90,
                           79, 89, 99, 97, 29 };
  
        // Display the sequence
        Console.WriteLine("The Sequence is: ");
  
        foreach(int s in sequence)
        {
            Console.WriteLine(s);
        }
  
        // Finding sum of the given sequence
        // Using Sum function
        int result = sequence.Sum();
        Console.WriteLine("The sum of the given "
                              + "sequence is: {0}",
                          result);
    }
}

输出：

The Sequence is: 
20
30
50
78
90
79
89
99
97
29
The sum of the given sequence is: 661

范例2：

// C# program to find the sum
// of the salary of the employee
using System;
using System.Linq;
using System.Collections.Generic;
  
// Employee details
public class employee {
    public int emp_id
    {
        get;
        set;
    }
    public string emp_name
    {
        get;
        set;
    }
    public string emp_gender
    {
        get;
        set;
    }
    public string emp_hire_date
    {
        get;
        set;
    }
    public int emp_salary
    {
        get;
        set;
    }
}
  
class GFG {
  
    // Main method
    static public void Main()
    {
        List emp = new List() {
            new employee() { emp_id = 209, emp_name = "Anjita", emp_gender = "Female", emp_hire_date = "12/3/2017", emp_salary = 20000 },
                new employee() { emp_id = 210, emp_name = "Soniya", emp_gender = "Female", emp_hire_date = "22/4/2018", emp_salary = 30000 },
                new employee() { emp_id = 211, emp_name = "Rohit", emp_gender = "Male", emp_hire_date = "3/5/2016", emp_salary = 40000 },
                new employee() { emp_id = 212, emp_name = "Supriya", emp_gender = "Female", emp_hire_date = "4/8/2017", emp_salary = 40000 },
                new employee() { emp_id = 213, emp_name = "Anil", emp_gender = "Male", emp_hire_date = "12/1/2016", emp_salary = 40000 },
                new employee() { emp_id = 214, emp_name = "Anju", emp_gender = "Female", emp_hire_date = "17/6/2015", emp_salary = 50000 },
        };
  
        // Find the sum of the salary
        // Using Sum () method
        var res = emp.Sum(a = > a.emp_salary);
        Console.WriteLine("Total salary of the Employees: {0}", res);
    }
}

输出：

Total salary of the Employees: 220000