集合的筛选

static void Main(string[] args)
{
 List<Person> personList = new List<Person>
 {
  new Person{Name="张三",Gender="男",Age=19},
  new Person{Name="李四",Gender="男",Age=34},
  new Person{Name="春丽",Gender="女",Age=20},
  new Person{Name="老王",Gender="男",Age=37},
  new Person{Name="小红",Gender="女",Age=18},
 };

//移除年龄大于25，且性别为男的person

//方法一：linq 扩展方法where()
//personList = personList.Where(p=>p.Gender=="男"&&p.Age>25).ToList();

#region 方法二：遍历集合找到所有要移除的元素，装到一个临时集合里，然后取两个集合的差集
List<Person> personList2 = new List<Person>();
foreach (Person p in personList)
{
  if (p.Gender == "男"&&p.Age >25)
  {
    personList2.Add(p);//装到临时集合里
  }
}
//取两个集合的差集
personList = personList.Except(personList2).ToList();//因为是延迟查询，所有ToList()一下赋值给原集合，原集合即为筛选后的集合

//输出
foreach (Person p in personList)
{
  Console.WriteLine(p.Name+" "+p.Gender+" "+p.Age);
}
Console.ReadKey();
}

}
#endregion

public class Person
{
private string namr;

public string Name
{
get { return namr; }
set { namr = value; }
}

private string gender;

public string Gender
{
get { return gender; }
set { gender = value; }
}

private int age;

public int Age
{
get { return age; }
set { age = value; }
}

}