Tutorial by Examples: ed

dispatch_group_t preapreWaitingGroup = dispatch_group_create(); dispatch_group_enter(preapreWaitingGroup); [self doAsynchronousTaskWithComplete:^(id someResults, NSError *error) { // Notify that this task has been completed. dispatch_group_leave(preapreWaitingGroup); }] dispatch...

Difference from PHP Array PHP's default Array type is actually implemented as ordered hash maps, which allow us to create arrays that consist of key/value pairs where values can be of any type and keys can be either numbers or strings. This is not traditionally how arrays are created, however. S...

Prerequisites Have a strong grasp of a programming language such as Python, C, C++, Ruby, or any of the other languages out there. Have your favorite code editor or IDE installed (one such example is VSCode) Stay motivated. Constructing a compiler is not easy, so keep pushing; it's worth the ef...

C++ #include "opencv2/objdetect/objdetect.hpp" #include "opencv2/highgui/highgui.hpp" #include "opencv2/imgproc/imgproc.hpp" #include <iostream> #include <stdio.h> using namespace std; using namespace cv; // Function Headers void detectAndDisp...

You can nest enumerations one inside an other, this allows you to structure hierarchical enums to be more organized and clear. enum Orchestra { enum Strings { case violin case viola case cello case doubleBasse } enum Keyboards { case...

This example has more tests available in unit testing. Employee.vb (Class Library) ''' <summary> ''' Employee Class ''' </summary> Public Class Employee ''' <summary> ''' First name of employee ''' </summary> Public Property FirstName As String = &q...

The advantage of using Apache over the builtin werkzeug server is that Apache is multi-threaded, meaning that multiple connections to the application can be made simultaneously. This is especially useful in applications that make use of XmlHttpRequest (AJAX) on the front-end. /etc/apache2/sites-ava...

A NullReferenceException is thrown when you try to access a non-static member (property, method, field or event) of a reference object but it is null. Car myFirstCar = new Car(); Car mySecondCar = null; Color myFirstColor = myFirstCar.Color; // No problem as myFirstCar exists / is not null Color...

Problem statement: Find the minimum (over x, y) of the function f(x,y), subject to g(x,y)=0, where f(x,y) = 2 * x**2 + 3 * y**2 and g(x,y) = x**2 + y**2 - 4. Solution: We will solve this problem by performing the following steps: Specify the Lagrangian function for the problem Determine the K...

In some cases, you would need to execute SQL query placed in string. EXEC, EXECUTE, or system procedure sp_executesql can execute any SQL query provided as string: sp_executesql N'SELECT * FROM sys.objects' -- or sp_executesql @stmt = N'SELECT * FROM sys.objects' -- or EXEC sp_executesql N'SEL...

You can execute SQL query as different user using AS USER = 'name of database user' EXEC(N'SELECT * FROM product') AS USER = 'dbo' SQL query will be executed under dbo database user. All permission checks applicable to dbo user will be checked on SQL query.

Writing a gzipped file To write a gzipped file, use the module IO::Compress::Gzip and create a filehandle by creating a new instance of IO::Compress::Gzip for the desired output file: use strict; use warnings; use open qw( :encoding(UTF-8) :std ); # Make UTF-8 default encoding use IO::Compres...

url: /api/data/v8.0/quotedetails json: { "[email protected]": "/products(11c0dbad-91df-e311-b8e5-6c3be5a8b200)", "[email protected]" : "/quotes(69b5e1ae-037f-e611-80ed-fc15b428dcdc)", "[email protected]" : "/uoms(73a5daea-6dd...

JSON_MODIFY function uses JSON text as input parameter, and modifies a value on the specified path using third argument: declare @json nvarchar(4000) = N'{"Id":1,"Name":"Toy Car","Price":34.99}' set @json = JSON_MODIFY(@json, '$.Price', 39.99) print @json -...

You can generate JSON object using standard SELECT query with FOR JSON clause and insert it into JSON text as third parameter: declare @json nvarchar(4000) = N'{"Id":17,"Name":"WWI"}' set @json = JSON_MODIFY(@json, '$.tables', (select name fr...

You can generate JSON object using standard SELECT query with FOR JSON clause and WITHOUT_ARRAY_WRAPPER option, and insert it into JSON text as a third parameter: declare @json nvarchar(4000) = N'{"Id":17,"Name":"WWI"}' set @json = JSON_MODIFY(@json, '$.table', ...

<!DOCTYPE html> <html lang="en-EN"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <meta name="csrf-param" content="_csrf"> <me...

There’s no API that can break the locked lease of blob storage in Microsoft Azure . This code snippet demonstrates break the locked lease of blob storage in Microsoft Azure (PowerShell). $key = (Get-AzureRmStorageAccountKey -ResourceGroupName $selectedStorageAccount.ResourceGroupName -name $select...

NSString *emailRegex = @"[A-Z0-9a-z]([A-Z0-9a-z._-]{0,64})+[A-Z0-9a-z]+@[A-Z0-9a-z]+([A-Za-z0-9.-]{0,64})+([A-Z0-9a-z])+\\.[A-Za-z]{2,4}"; NSString *firstNameRegex = @"[0-9A-Za-z\"'-]{2,32}$"; NSString *firstNameRegex = @"[ 0-9A-Za-z]{2,32}$"; NSString *lastNa...

A linked list is either: the empty list, represented by None, or a node that contains a cargo object and a reference to a linked list. #! /usr/bin/env python class Node: def __init__(self, cargo=None, next=None): self.car = cargo self.cdr = next d...