Tutorial by Examples: en

Recursion occurs when a function call causes that same function to be called again before the original function call terminates. For example, consider the well-known mathematical expression x! (i.e. the factorial operation). The factorial operation is defined for all nonnegative integers as follows:...

1) Use ng-repeat sparingly Using ng-repeat in views generally results in poor performance, particularly when there are nested ng-repeat's. This is super slow! <div ng-repeat="user in userCollection"> <div ng-repeat="details in user"> {{details}} </div...

$scope.$emit Using $scope.$emit will fire an event name upwards through the scope hierarchy and notify to the $scope.The event life cycle starts at the scope on which $emit was called. Working wireframe : $scope.$broadcast Using $scope.$broadcast will fire an event down the $scope. We can list...

package { import flash.events.Event; public class CustomEvent extends Event { public static const START:String = "START"; public static const STOP:String = "STOP"; public var data:*; public function CustomEvent(type:Strin...

function isDaylightSavings(d:Date):Boolean { var months:uint = 12; var offset:uint = d.timezoneOffset; var offsetCheck:Number; while (months--) { offsetCheck = (new Date(d.getFullYear(), months, 1)).timezoneOffset; if (offsetCheck != offset) ret...

The right-hand side of the assignment in a for loop can be any row vector. The left-hand side of the assignment can be any valid variable name. The for loop assigns a different element of this vector to the variable each run. other_row_vector = [4, 3, 5, 1, 2]; for any_name = other_row_vector ...

public function up() { $this->dropColumn('post', 'position'); $this->renameColumn('post', 'owner_id', 'user_id'); $this->alterColumn('post', 'updated', $this->timestamp()->notNull()->defaultValue('0000-00-00 00:00:00')); }

Imagine you have the following HTML: <div> <label>Name:</label> John Smith </div> And you need to locate the text "John Smith" after the label element. In this case, you can locate the label element by text and then use .next_sibling property: from ...

BeautifulSoup has a limited support for CSS selectors, but covers most commonly used ones. Use select() method to find multiple elements and select_one() to find a single element. Basic example: from bs4 import BeautifulSoup data = """ <ul> <li class="item&quo...

When the destructor for std::thread is invoked, a call to either join() or detach() must have been made. If a thread has not been joined or detached, then by default std::terminate will be called. Using RAII, this is generally simple enough to accomplish: class thread_joiner { public: thre...

In Julia, the @show macro is often useful for debugging purposes. It displays both the expression to be evaluated and its result, finally returning the value of the result: julia> @show 1 + 1 1 + 1 = 2 2 It is straightforward to create our own version of @show: julia> macro myshow(exp...

Partial credit to this SO answer. List Concatenation aggregates a column or expression by combining the values into a single string for each group. A string to delimit each value (either blank or a comma when omitted) and the order of the values in the result can be specified. While it is not part ...

Sometimes you want to add an element to the beginning of an array without modifying any of the current elements (order) within the array. Whenever this is the case, you can use array_unshift(). array_unshift() prepends passed elements to the front of the array. Note that the list of elements is ...

When running from the CLI, PHP exhibits some different behaviours than when run from a web server. These differences should be kept in mind, especially in the case where the same script might be run from both environments. No directory change When running a script from a web server, the current w...

Builtin container comes with a set of builtin features : Lifetime control public void ConfigureServices(IServiceCollection services) { // ... services.AddTransient<ITestService, TestService>(); // or services.AddScoped<ITestService, TestSer...

Once registered a dependency can be retrieved by adding parameters on the Controller constructor. // ... using System; using Microsoft.Extensions.DependencyInjection; namespace Core.Controllers { public class HomeController : Controller { public HomeController(ITestServic...

Consider the character class [aeiou]. This character class can be used in a regular expression to match a set of similarly spelled words. b[aeiou]t matches: bat bet bit bot but It does not match: bout btt bt Character classes on their own match one and only one character at a time...

Given any value of type Int or Long to render a human readable string: fun Long.humanReadable(): String { if (this <= 0) return "0" val units = arrayOf("B", "KB", "MB", "GB", "TB", "EB") val digitGroups = (Mat...

A common use case for extension methods is to improve an existing API. Here are examples of adding exist, notExists and deleteRecursively to the Java 7+ Path class: fun Path.exists(): Boolean = Files.exists(this) fun Path.notExists(): Boolean = !this.exists() fun Path.deleteRecursively(): Bool...

In Kotlin you could write code like: val x: Path = Paths.get("dirName").apply { if (Files.notExists(this)) throw IllegalStateException("The important file does not exist") } But the use of apply is not that clear as to your intent. Sometimes it is clearer to create a ...