int[] grades = { 59, 82, 70, 56, 92, 98, 85 };

// Get all grades less than 80 by first
// sorting the grades in descending order and then
// taking all the grades after the first grade
// that is less than 80.
IEnumerable<int> lowerGrades =
    grades.AsQueryable()
    .OrderByDescending(grade => grade)
    .SkipWhile(grade => grade >= 80);

Console.WriteLine("All grades below 80:");
foreach (int grade in lowerGrades)
    Console.WriteLine(grade);

int[] amounts = { 5000, 2500, 9000, 8000, 
                    6500, 4000, 1500, 5500 };

// Skip over amounts in the array until the first amount
// that is less than or equal to the product of its
// index in the array and 1000. Take the remaining items.
IEnumerable<int> query =
    amounts.AsQueryable()
    .SkipWhile((amount, index) => amount > index * 1000);

foreach (int amount in query)
    Console.WriteLine(amount);

//引入命名空间
using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Linq;

public class MainClass{
   public static void Main(){
       int[] numbers = { 1, 3, 5, 4};
       var query = numbers.TakeWhile(( n, index) => n >= index);

       var query2 = numbers.SkipWhile(( n, index) => n >= index);
    }
}

//引入命名空间
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

public class MainClass{
public static void Main() {

            int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
            
            var allButFirst3Numbers = numbers.SkipWhile(n => n % 3 != 0);
            
            Console.WriteLine("All elements starting from first element divisible by 3:");
            foreach (var n in allButFirst3Numbers) {
                Console.WriteLine(n);
            }
        }
}