101 LINQ Samples: Partitioning Operators

Take - Simple

This sample uses Take to get only the first 3 elements of the array.

public void Linq20() {     int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };       var first3Numbers = numbers.Take(3);       Console.WriteLine("First 3 numbers:");     foreach (var n in first3Numbers)     {         Console.WriteLine(n);     } }

Result

First 3 numbers: 
5 
4 
1

Take - Nested

This sample uses Take to get the first 3 orders from customers in Washington.

public void Linq21() {     List<Customer> customers = GetCustomerList();       var first3WAOrders = (         from c in customers         from o in c.Orders         where c.Region == "WA"         select new { c.CustomerID, o.OrderID, o.OrderDate })         .Take(3);       Console.WriteLine("First 3 orders in WA:");     foreach (var order in first3WAOrders)     {         ObjectDumper.Write(order);     } }

Result

First 3 orders in WA: 
CustomerID=LAZYK OrderID=10482 OrderDate=3/21/1997 
CustomerID=LAZYK OrderID=10545 OrderDate=5/22/1997 
CustomerID=TRAIH OrderID=10574 OrderDate=6/19/1997

Skip - Simple

This sample uses Skip to get all but the first 4 elements of the array.

public void Linq22() {     int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };       var allButFirst4Numbers = numbers.Skip(4);       Console.WriteLine("All but first 4 numbers:");     foreach (var n in allButFirst4Numbers)     {         Console.WriteLine(n);     } }

Result

All but first 4 numbers: 
9 
8 
6 
7 
2 
0

Skip - Nested

This sample uses Take to get all but the first 2 orders from customers in Washington.

public void Linq23() {     List<Customer> customers = GetCustomerList();       var waOrders =         from c in customers         from o in c.Orders         where c.Region == "WA"         select new { c.CustomerID, o.OrderID, o.OrderDate };       var allButFirst2Orders = waOrders.Skip(2);       Console.WriteLine("All but first 2 orders in WA:");     foreach (var order in allButFirst2Orders)     {         ObjectDumper.Write(order);     } }

Result

All but first 2 orders in WA:
CustomerID=TRAIH OrderID=10574 OrderDate=6/19/1997
CustomerID=TRAIH OrderID=10577 OrderDate=6/23/1997
CustomerID=TRAIH OrderID=10822 OrderDate=1/8/1998
CustomerID=WHITC OrderID=10269 OrderDate=7/31/1996
CustomerID=WHITC OrderID=10344 OrderDate=11/1/1996
CustomerID=WHITC OrderID=10469 OrderDate=3/10/1997
CustomerID=WHITC OrderID=10483 OrderDate=3/24/1997
CustomerID=WHITC OrderID=10504 OrderDate=4/11/1997
CustomerID=WHITC OrderID=10596 OrderDate=7/11/1997
CustomerID=WHITC OrderID=10693 OrderDate=10/6/1997
CustomerID=WHITC OrderID=10696 OrderDate=10/8/1997
CustomerID=WHITC OrderID=10723 OrderDate=10/30/1997
CustomerID=WHITC OrderID=10740 OrderDate=11/13/1997
CustomerID=WHITC OrderID=10861 OrderDate=1/30/1998
CustomerID=WHITC OrderID=10904 OrderDate=2/24/1998
CustomerID=WHITC OrderID=11032 OrderDate=4/17/1998
CustomerID=WHITC OrderID=11066 OrderDate=5/1/1998

TakeWhile - Simple

This sample uses TakeWhile to return elements starting from the beginning of the array until a number is hit that is not less than 6.

public void Linq24() {     int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };       var firstNumbersLessThan6 = numbers.TakeWhile(n => n < 6);       Console.WriteLine("First numbers less than 6:");     foreach (var n in firstNumbersLessThan6)     {         Console.WriteLine(n);     } }

Result

First numbers less than 6:
5
4
1
3

TakeWhile - Indexed

This sample uses TakeWhile to return elements starting from the beginning of the array until a number is hit that is less than its position in the array.

public void Linq25() {     int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };       var firstSmallNumbers = numbers.TakeWhile((n, index) => n >= index);       Console.WriteLine("First numbers not less than their position:");     foreach (var n in firstSmallNumbers)     {         Console.WriteLine(n);     } }

Result

First numbers not less than their position: 
5 
4

SkipWhile - Simple

This sample uses SkipWhile to get the elements of the array starting from the first element divisible by 3.

public void Linq26() {     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);     } }

Result

All elements starting from first element divisible by 3:
3
9
8
6
7
2
0

SkipWhile - Indexed

This sample uses SkipWhile to get the elements of the array starting from the first element less than its position.

public void Linq27() {     int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };       var laterNumbers = numbers.SkipWhile((n, index) => n >= index);       Console.WriteLine("All elements starting from first element less than its position:");     foreach (var n in laterNumbers)     {         Console.WriteLine(n);     } }

Result

All elements starting from first element less than its position:
1
3
9
8
6
7
2
0

转载于:https://www.cnblogs.com/zjz008/archive/2011/03/13/1982897.html