[Back to LINQ examples] View Original LINQ Code
Take - Simple
This sample prints the first 3 elements of the array.
This is one of the LINQ examples designed to show LINQ operating over standard Java collections; it uses the Take operator. In this case the batch version is just ordinary Java iteration.
public void Batch20() {
int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
for (int i=0; i<3; i++)
print("{0}", numbers[i]);
}
Original LINQ code:
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);
}
}
Take - Nested
This sample prints the first 3 orders from customers in Washington.
The LINQ version uses Take. The batch version uses first.
public void Batch21() {
print("First 3 orders in WA:");
for (Northwind db : connection)
for (Order o : db.Orders.first(3))
if (o.Customer.Region == "WA")
print("CustomerID={0} OrderID={1} OrderDate={2}",
o.Customer.CustomerID,
o.OrderID,
o.OrderDate);
}
Generated SQL code:
SELECT
T2.CustomerID AS g0,
T1.OrderID AS g1,
T1.OrderDate AS g2
FROM Orders T1
INNER JOIN Customers T2 ON (T2.CustomerID=T1.CustomerID)
WHERE (T2.Region="WA")
LIMIT 3
Original LINQ code:
private 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);
}
}
Skip - Simple
This sample prints all but the first 4 elements of the array.
This is one of the LINQ examples designed to show LINQ operating over standard Java collections; it uses the Skip operator. In this case the batch version is just ordinary Java iteration.
public void Batch22() {
int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
print("All but first 4 numbers:");
for (int i=4; i<numbers.length; i++)
print("{0}", numbers[i]);
}
Original LINQ code:
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);
}
}
Skip - Nested
This sample gets all but the first 2 orders from customers in Washington
public void Batch23() {
int index = 0;
for (Northwind db : connection) {
print("All but first 2 orders in WA:");
for (Customer c : db.Customers)
if (c.Region == "WA")
for (Order o : c.Orders)
if (index > 1)
print("CustomerID={0} OrderID={1} OrderDate={2}",
o.Customer.CustomerID,
o.OrderID,
o.OrderDate);
else
index++;
}
}
Original LINQ code:
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);
}
}
TakeWhile - Simple
This sample return elements starting from the beginning of the array until a number is hit that is not less than 6.
public void Batch24() {
int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
print("First numbers less than 6:");
for (int i=0; i<numbers.length; i++) {
if (numbers[i] > 6)
break;
print("{0}", numbers[i]);
}
}
Original LINQ code:
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);
}
TakeWhile - Indexed
This sample returns elements starting from the beginning of the array until a number is hit that is less than its position in the array.
public void Batch25() {
int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
print("First numbers not less than their position:");
for (int i=0; i<numbers.length; i++) {
if (numbers[i] < i)
break;
print("{0}", numbers[i]);
}
}
Original LINQ code:
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);
}
SkipWhile - Simple
This sample uses SkipWhile to get the elements of the array starting from the first element divisible by 3.
public void Batch26() {
int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
print("All elements starting from first element divisible by 3:");
int i = 0;
while (numbers[i] % 3 != 0)
i++;
for (; i<numbers.length; i++) {
print("{0}", numbers[i]);
}
}
Original LINQ code:
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);
}
SkipWhile - Indexed
This sample gets the elements of the array starting from the first element less than its position.
public void Batch27() {
int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
print("All elements starting from first element less than its position:");
int i=0;
while (numbers[i] >= i)
i++;
for (; i<numbers.length; i++) {
print("{0}", numbers[i]);
}
}
Original LINQ code:
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);
}
