Tutorial by Examples: er

Static method can be inherited similar to normal methods, however unlike normal methods it is impossible to create "abstract" methods in order to force static method overriding. Writing a method with the same signature as a static method in a super class appears to be a form of overriding,...

Consider the below list comprehension: >>> def f(x): ... import time ... time.sleep(.1) # Simulate expensive function ... return x**2 >>> [f(x) for x in range(1000) if f(x) > 10] [16, 25, 36, ...] This results in two calls to f(x) for 1,000 values of...

This code creates a sticky footer. When the content doesn't reach the end of the viewport, the footer sticks to the bottom of the viewport. When the content extends past the bottom of the viewport, the footer is also pushed out of the viewport. View Result HTML: <div class="header"&gt...

Undoing a merge not yet pushed to a remote If you haven't yet pushed your merge to the remote repository then you can follow the same procedure as in undo the commit although there are some subtle differences. A reset is the simplest option as it will undo both the merge commit and any commits add...

In this example, we're going to set up an Express server integration to display how to process a payment with PayPal, using the PayPal Node SDK. We will use a static JSON structure for the payment details for the sake of brevity. There are three general steps that we will follow when building out t...

Data Manipulation Language (DML for short) includes operations such as INSERT, UPDATE and DELETE: -- Create a table HelloWorld CREATE TABLE HelloWorld ( Id INT IDENTITY, Description VARCHAR(1000) ) -- DML Operation INSERT, inserting a row into the table INSERT INTO HelloWorld (D...

do './config.pl'; This will read in the contents of the config.pl file and execute it. (See also: perldoc -f do.) N.B.: Avoid do unless golfing or something as there is no error checking. For including library modules, use require or use.

If you need to use the ^ character in a character class (Character classes ), either put it somewhere other than the beginning of the class: [12^3] Or escape the ^ using a backslash \: [\^123] If you want to match the caret character itself outside a character class, you need to escape it: ...

If the preprocessor encounters an #error directive, compilation is halted and the diagnostic message included is printed. #define DEBUG #ifdef DEBUG #error "Debug Builds Not Supported" #endif int main(void) { return 0; } Possible output: $ gcc error.c error.c: error: #e...

Swift's built-in numeric types are: Word-sized (architecture-dependent) signed Int and unsigned UInt. Fixed-size signed integers Int8, Int16, Int32, Int64, and unsigned integers UInt8, UInt16, UInt32, UInt64. Floating-point types Float32/Float, Float64/Double, and Float80 (x86-only). Literal...

func doSomething1(value: Double) { /* ... */ } func doSomething2(value: UInt) { /* ... */ } let x = 42 // x is an Int doSomething1(Double(x)) // convert x to a Double doSomething2(UInt(x)) // convert x to a UInt Integer initializers produce a runtime error if the value ove...

Use String initializers for converting numbers into strings: String(1635999) // returns "1635999" String(1635999, radix: 10) // returns "1635999" String(1635999, radix: 2) // returns "110001111011010011111&...

Indexes can have several characteristics that can be set either at creation, or by altering existing indexes. CREATE CLUSTERED INDEX ix_clust_employee_id ON Employees(EmployeeId, Email); The above SQL statement creates a new clustered index on Employees. Clustered indexes are indexes that dict...

UPDATE Customers SET Email = "[email protected]" WHERE id = 1; This will fail if an unique index is set on the Email column of Customers. However, alternate behavior can be defined for this case: UPDATE Customers SET Email = "[email protected]" WHERE id = 1 ON DUP...

Classes are reference types, meaning that multiple variables can refer to the same instance. class Dog { var name = "" } let firstDog = Dog() firstDog.name = "Fido" let otherDog = firstDog // otherDog points to the same Dog instance otherDog.name = "Rover" // modifying otherDog also...

Classes can define properties that instances of the class can use. In this example, Dog has two properties: name and dogYearAge: class Dog { var name = "" var dogYearAge = 0 } You can access the properties with dot syntax: let dog = Dog() print(dog.name) print(dog.dogYear...

The key to correctly stretching is in the top and left border. The top border controls horizontal stretching and the left border controls vertical stretching. This example creates rounded corners suitable for a Toast. The parts of the image that are below the top border and to the right of the ...

The Spinner can be reskinned according to your own style requirements using a Nine Patch. As an example, see this Nine Patch: As you can see, it has 3 extremely small areas of stretching marked. The top border has only left of the icon marked. That indicates that I want the left side (complete ...

var date1 = new Date(); date1.toJSON(); Returns: "2016-04-14T23:49:08.596Z"

Composer generates a vendor/autoload.php file. You might simply include this file and you will get autoloading for free. require __DIR__ . '/vendor/autoload.php'; This makes working with third-party dependencies very easy. You can also add your own code to the Autoloader by adding an autoload ...