Tutorial by Examples: r

(This pitfall applies equally to all primitive wrapper types, but we will illustrate it for Integer and int.) When working with Integer objects, it is tempting to use == to compare values, because that is what you would do with int values. And in some cases this will seem to work: Integer int1_1 =...

1. Fix your contexts: Try using the appropriate context: For example since a Toast can be seen in many activities instead of in just one, use getApplicationContext() for toasts, and since services can keep running even though an activity has ended start a service with: Intent myService = new Inten...

Custom constructors can be made for derived types by using an interface to overload the type name. This way, keyword arguments that don't correspond to components can be used when constructing an object of that type. module ball_mod implicit none ! only export the derived type, and not any ...

The .format() method can interpret a number in different formats, such as: >>> '{:c}'.format(65) # Unicode character 'A' >>> '{:d}'.format(0x0a) # base 10 '10' >>> '{:n}'.format(0x0a) # base 10 using current locale for separators '10' Format integers to d...

union U { int a; short b; float c; }; U u; u.a = 10; if (u.b == 10) { // this is undefined behavior since 'a' was the last member to be // written to. A lot of compilers will allow this and might issue a // warning, but the result will be "as expected"; thi...

Properties can be set when an object is instantiated. var redCar = new Car { Wheels = 2, Year = 2016, Color = Color.Red };

functions.php //Localize the AJAX URL and Nonce add_action('wp_enqueue_scripts', 'example_localize_ajax'); function example_localize_ajax(){ wp_localize_script('jquery', 'ajax', array( 'url' => admin_url('admin-ajax.php'), 'nonce' => wp_create_nonce('example_ajax_nonc...

If you aren't sure whether a value is of the type you think it is, you can safely cast it using the as operator. If the value is not of that type, the resulting value will be null. object value = "-1"; int? number = value as int?; if(number != null) { Console.WriteLine(Math.Abs(nu...

Explicit casting operators can be used to perform conversions of numeric types, even though they don't extend or implement one another. double value = -1.1; int number = (int) value; Note that in cases where the destination type has less precision than the original type, precision will be lost....

In the most basic form, it is possible to select a single variable from a table by calling the object's get_var method passing in an SQL query. global $wpdb; $user = $wpdb->get_var( "SELECT ID FROM $wpdb->users WHERE user_email='[email protected]'" ); It is very important to note that...

public class Singleton { private static class InstanceHolder { static final Singleton INSTANCE = new Singleton(); } public static Singleton getInstance() { return InstanceHolder.INSTANCE; } private Singleton() {} } This initializes the INSTANCE vari...

Prerequisites The Windows version of Elasticsearch can be obtained from this link: https://www.elastic.co/downloads/elasticsearch. The latest stable release is always at the top. As we are installing on Windows, we need the .ZIP archive. Click the link in the Downloads: section and save the file t...

Getting all the information of current user in wordpress using the predefined function wp_get_current_user(); <?php $current_user = wp_get_current_user(); echo "Username :".$current_user->user_login; echo "Username :".$current_user-&g...

A generator is a combination of two things - an Iterator and an Observer. Iterator An iterator is something when invoked returns an iterable. An iterable is something you can iterate upon. From ES6/ES2015 onwards, all collections (Array, Map, Set, WeakMap, WeakSet) conform to the Iterable contract...

function social_profiles( $contactmethods ) { $contactmethods['facebook_profile'] = 'Facebook Profile URL'; $contactmethods['twitter_profile'] = 'Twitter Profile URL'; $contactmethods['google_profile'] = 'Google Profile URL'; $contactmethods['linkedin_profile'] = 'Li...

function remove_contact_methods( $contactmethods ) { unset($contactmethods['facebook_profile']); unset($contactmethods['twitter_profile']); return $contactmethods; } add_filter( 'user_contactmethods', 'remove_contact_methods', 10, 1);

OpenSSL is an open source project that provides a robust, commercial-grade, and full-featured toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols. It is also a general-purpose cryptography library. The OpenSSL toolkit is licensed under an Apache-style license, wh...

A Stream of items that are in turn streamable can be flattened into a single continuous Stream: Array of List of Items can be converted into a single List. List<String> list1 = Arrays.asList("one", "two"); List<String> list2 = Arrays.asList("three&quot...

To create a Grails application, use the grails create-app command. The following command creates a Grails application, named myapp in the current directory: grails create-app fancy-app Running it, is as simple as visiting the, newly created, application directory: cd fancy-app and then grai...

The .split() method splits a string into an array of substrings. By default .split() will break the string into substrings on spaces (" "), which is equivalent to calling .split(" "). The parameter passed to .split() specifies the character, or the regular expression, to use for...