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OpenCV (Open Source Computer Vision Library) is an open source computer vision and machine learning software library. It was built for various purpose such as machine learning, computer vision, algorithm, mathematical operations, video capturing, image processing etc. Over the years it has become ve...

Objective C: view.backgroundColor = [UIColor redColor]; Swift: view.backgroundColor! = UIColor.redColor() Swift 3 view.backgroundColor = UIColor.redColor

Pattern rules can have multiple targets but, unlike normal rules, the recipe is responsible for making all the targets. For example: debug/%.o release/%.o: %.c $(CC) $(CFLAGS_DEBUG) -c $< -o debug/$*.o $(CC) $(CFLAGS_RELEASE) -c $< -o release/$*.o Is a valid rule, which will buil...

If you want to add a UIImageView to the center of the screen with width and height of 100 pixel, you need to set center x constraint and center y constraint to the superview from the UIImageView and width, height constraint to the UIIMageView. Here is the code. There is way to do this in storyboard ...

PHPUnit provides the following functions to watch for thrown exceptions, which were released with 5.2.0: expectException($exception) expectExceptionMessage($message) expectExceptionCode($code) expectExceptionMessageRegExp($messageRegExp) These are used to watch for an exception to be thrown...

public class CreateArrayWithValues { public static void main(String[] args){ // Initializes an array of Strings with values String[] myArray = {"this", "array", "has", "six", "initial", "values"}; System.out....

Xamarin is becoming more and more popular - it is hard to decide when to use Xamarin.Forms and when Xamarin.Platform (so Xamarin.iOS and Xamarin.Android). First of all you should know for what kind of applications you can use Xamarin.Forms: Prototypes - to visualize how your application will l...

public static IWebDriver dismissAlert(this IWebDriver driver) { try { IAlert alert = driver.SwitchTo().Alert(); alert.Dismiss(); } catch {} return driver; } public static IWebDriver acceptAlert(this IWebDriver driver) { try { IAlert a...

The function show is automatically exported when use Data::Show; is executed. This function takes a variable as its sole argument and it outputs: the name of the variable the contents of that variable (in a readable format) the line of the file that show is run from the file show is run from ...

Sympy is a Python library for doing symbolic — rather than numeric — calculations. For instance, consider the quadratic equation in x, x**2 + HELLO * x + WORLD = 0 where HELLO and WORLD are constants. What's the solution of this equation? In Python, using Sympy we can code, from sympy import s...

Dynamic queries are SET @sql = N'SELECT COUNT(*) FROM AppUsers WHERE Username = ''' + @user + ''' AND Password = ''' + @pass + '''' EXEC(@sql) If value of user variable is myusername'' OR 1=1 -- the following query will be executed: SELECT COUNT(*) FROM AppUsers WHERE Username = 'myusername...

In order to avoid injection and escaping problems, dynamic SQL queries should be executed with parameters, e.g.: SET @sql = N'SELECT COUNT(*) FROM AppUsers WHERE Username = @user AND Password = @pass EXEC sp_executesql @sql, '@user nvarchar(50), @pass nvarchar(50)', @username, @password Second ...

There are many reasons a write operation may fail. A frequent one is because your security rules reject the operation, for example because you're not authenticated (by default a database can only be accessed by an authenticated user). You can see these security rule violations in the output of your...

SQL Server 2008 The ROW_NUMBER function can assign an incrementing number to each row in a result set. Combined with a Common Table Expression that uses a BETWEEN operator, it is possible to create 'pages' of result sets. For example: page one containing results 1-10, page two containing results 11...

SQL Server 2012 The OFFSET FETCH clause implements pagination in a more concise manner. With it, it's possible to skip N1 rows (specified in OFFSET) and return the next N2 rows (specified in FETCH): SELECT * FROM sys.objects ORDER BY object_id OFFSET 40 ROWS FETCH NEXT 10 ROWS ONLY The ORDER...

In earlier versions of SQL Server, developers had to use double sorting combined with the TOP keyword to return rows in a page: SELECT TOP 10 * FROM ( SELECT TOP 50 object_id, name, type, create_date FROM sys.objects ORDER BY name ASC ) AS data ...

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...

There are two equivalent ways to calculate the amount of time unit between two LocalTime: (1) through until(Temporal, TemporalUnit) method and through (2) TemporalUnit.between(Temporal, Temporal). import java.time.LocalTime; import java.time.temporal.ChronoUnit; public class AmountOfTime { ...

Specifies that the query is optimized for fast retrieval of the first number_rows. This is a nonnegative integer. After the first number_rows are returned, the query continues execution and produces its full result set. select OrderID, AVG(Quantity) from Sales.OrderLines group by OrderID OPTION ...

JSON_MODIFY function enables you to insert JSON objects into JSON text: declare @json nvarchar(4000) = N'{"Id":1,"Name":"Toy Car"}' set @json = JSON_MODIFY(@json, '$.Price', JSON_QUERY('{"Min":34.99,"Recommended":45.49}'))...