在LINQ中，Set运算符是查询表达式中的那些运算符，它们基于相同或不同集合或序列或集合中等效元素的存在或不存在返回结果集。标准查询运算符包含以下集合运算符：
- 联盟
- 相交
- 除了
- 清楚的
除运算符外
Except运算符返回设置的差。换句话说，我们可以说它返回了包含未出现在第二个集合或集合中的元素的集合或集合。
- 它不支持C＃和VB.Net语言的查询语法。但是您可以对查询变量使用Except方法，也可以将查询括在方括号中，然后调用Except方法。
- 它支持C＃和VB.Net语言的方法语法。
- 它同时存在于Queryable和Enumerable类中。
- 它是通过使用延迟执行来实现的。
- 使用复杂类型的集合时，必须使用IEqualityComparer接口，否则，Except方法将给您错误的结果。
范例1：
// C# program to find the difference
// of the given sequences
using System;
using System.Linq;
class GFG {
static public void Main()
{
// Data source
char[] sequence1 = {'m', 'q', 'o', 's', 'y', 'a'};
char[] sequence2 = {'p', 't', 'r', 's', 'y', 'z'};
// Display the sequences
Console.WriteLine("Sequence 1 is: ");
foreach(var s1 in sequence1)
{
Console.WriteLine(s1);
}
Console.WriteLine("Sequence 2 is: ");
foreach(var s2 in sequence2)
{
Console.WriteLine(s2);
}
// Get the difference of the given
// sequences Using Except function
var result = sequence1.Except(sequence2);
Console.WriteLine("New Sequence: ");
foreach(var val in result)
{
Console.WriteLine(val);
}
}
}
输出：
Sequence 1 is:
m
q
o
s
y
a
Sequence 2 is:
p
t
r
s
y
z
New Sequence:
m
q
o
a
范例2：
// C# program to find the languages which is
// not known by employees of the Department 2
using System;
using System.Linq;
using System.Collections.Generic;
// Employee details
// Department 1
public class Employee1 {
public int emp_id1
{
get;
set;
}
public string emp_name1
{
get;
set;
}
public string emp_lang1
{
get;
set;
}
}
// Employee details
// Department 2
public class Employee2 {
public int emp_id2
{
get;
set;
}
public string emp_name2
{
get;
set;
}
public string emp_lang2
{
get;
set;
}
}
public class GFG {
// Main method
static public void Main()
{
List emp1 = new List() {
new Employee1() {emp_id1 = 209, emp_name1 = "Anjita",
emp_lang1 = "C#"},
new Employee1() {emp_id1 = 210, emp_name1 = "Soniya",
emp_lang1 = "C"},
new Employee1() {emp_id1 = 211, emp_name1 = "Rohit",
emp_lang1 = "Java"},
};
List emp2 = new List() {
new Employee2() {emp_id2 = 290, emp_name2 = "Anjita",
emp_lang2 = "C#"},
new Employee2() {emp_id2 = 212, emp_name2 = "MaMa",
emp_lang2 = "Python"},
new Employee2() {emp_id2 = 233, emp_name2 = "Rima",
emp_lang2 = "Java"},
};
// Query to find the languages that is not
// known by employees of the department 2
// Using Except method
var res = emp1.Select(e => e.emp_lang1).Except(emp2.Select(e => e.emp_lang2));
Console.WriteLine("Language: ");
foreach(var val in res)
{
Console.WriteLine(val);
}
}
}
输出：
Language:
C