Tutorial by Examples: d

A custom component that takes the type of a component as input and creates an instance of that component type inside itself. When the input is updated, the previously added dynamic component is removed and the new one added instead. @Component({ selector: 'dcl-wrapper', template: `<div #...

The main difference is that double-quoted String literals support string interpolations and the full set of escape sequences. For instance, they can include arbitrary Ruby expressions via interpolation: # Single-quoted strings don't support interpolation puts 'Now is #{Time.now}' # Now is #{Time...

Few people have issue regarding error message not displaying if existing value is being entered in textbox. So, For Example I'm not allowing user to enter existing email. signup.php (Page where you wanted to sign up new user without existing email id) Remove use yii\bootstrap\ActiveForm; (if p...

Some people have issues regarding error messages not being displayed if an existing value is being entered. For example I'm not allowing a user signup with an existing email. View <?php ...................... <?= $form->field($modelUser, 'email')->textInput(['class'=&gt...

In Python 2, range function returns a list while xrange creates a special xrange object, which is an immutable sequence, which unlike other built-in sequence types, doesn't support slicing and has neither index nor count methods: Python 2.x2.3 print(range(1, 10)) # Out: [1, 2, 3, 4, 5, 6, 7, 8, 9...

With any variadic function, the function must know how to interpret the variable arguments list. With the printf() or scanf() functions, the format string tells the function what to expect. The simplest technique is to pass an explicit count of the other arguments (which are normally all the same ...

using namespace System; int main(array<String^>^ args) { Console::WriteLine("Hello World"); }

Module serves as a container of different parts of your app such as controllers, services, filters, directives, etc. Modules can be referenced by other modules through Angular's dependency injection mechanism. Creating a module: angular .module('app', []); Array [] passed in above example ...

The static (compile-time) type is used rather than the dynamic (run-time type) to match parameters. public class Base { public virtual string GetName() { return "Base"; } } public class Derived : Base { public override string GetName() { ...

It is possible to treat a GoogleMap as an Android view if we make use of the provided MapView class. Its usage is very similar to MapFragment. In your layout use MapView as follows: <com.google.android.gms.maps.MapView xmlns:android="http://schemas.android.com/apk/res/android" ...

Prefer public class Order { public OrderLine AddOrderLine(OrderLine orderLine) { if (orderLine == null) throw new ArgumentNullException(nameof(orderLine)); ... } } Over public class Order { public OrderLine AddOrderLine(OrderLine orderLine) { ...

The function php_sapi_name() and the constant PHP_SAPI both return the type of interface (Server API) that is being used by PHP. They can be used to restrict the execution of a script to the command line, by checking whether the output of the function is equal to cli. if (php_sapi_name() === 'cli')...

A data.table is an enhanced version of the data.frame class from base R. As such, its class() attribute is the vector "data.table" "data.frame" and functions that work on a data.frame will also work with a data.table. There are many ways to create, load or coerce to a data.table....

float float is an alias to the .NET datatype System.Single. It allows IEEE 754 single-precision floating point numbers to be stored. This data type is present in mscorlib.dll which is implicitly referenced by every C# project when you create them. Approximate range: -3.4 × 1038 to 3.4 × 1038 Deci...

This is the Python 2 syntax, note the commas , on the raise and except lines: Python 2.x2.3 try: raise IOError, "input/output error" except IOError, exc: print exc In Python 3, the , syntax is dropped and replaced by parenthesis and the as keyword: try: raise IOErro...

Rails uses sqlite3 as the default database, but you can generate a new rails application with a database of your choice. Just add the -d option followed by the name of the database. $ rails new MyApp -T -d postgresql This is a (non-exhaustive) list of available database options: mysql oracle...

Suppose you have a repository structure like this: examples/ output.log src/ <files not shown> output.log README.md output.log in the examples directory is valid and required for the project to gather an understanding while the one beneath src/ is created while debugging a...

Special care needs to be taken when there is a possibility that an array become an empty array when it comes to logical operators. It is often expected that if all(A) is true then any(A) must be true and if any(A) is false, all(A) must also be false. That is not the case in MATLAB with empty arrays....

The checked out file will overwrite not yet commited changes you did in this file. This command will check out the file file.example (which is located in the directory path/to/) and overwrite any changes you might have made to this file. git checkout some-branch path/to/file some-branch can be ...

To develop an application for iOS, you should start with an application called Xcode. There are other alternative tools you can use, but Xcode is Apple's official tool. Note, however, that it only runs on macOS. The latest official version is Xcode 8.3.3 with Xcode 9 (currently in beta) due to be re...