Tutorial by Examples: w

Higher-order functions can be used to ensure that system resources are disposed, even when a treatment raises an exception. The pattern used by with_output_file allows a clean separation of concerns: the higher-order with_output_file functions takes care of managing the system resources bound to fi...

Although modules are ideal, if the library you are using is referenced by a global variable (like $ or _), because it was loaded by a script tag, you can create an ambient declaration in order to refer to it: declare const _: any;

Once you have Sails installed, just type $ sails new <project_name> This will create a skeleton Sails project in a new folder called <project_name>. You can also create a new project in an empty folder by typing $ sails new

A row of cells in a tabular container. <table> <thead> <!-- etc --> </thead> <tbody> <tr role="row"> <!-- etc --> </tr> </tbody> </table>

A group containing one or more row elements in a grid. <table> <thead role="rowgroup"> <!-- etc --> </thead> <tbody role="rowgroup"> <!-- etc --> </tbody> </table>

A cell containing header information for a row in a grid. <table role="grid"> <thead> <!-- etc --> </thead> <tbody> <tr> <th role="rowheader">Day 1</th> <td>65</td> </tr> ...

A type of checkbox that represents on/off values, as opposed to checked/unchecked values. <select role="switch" aria-checked="false"> <option>On</option> <option selected>Off</option> </select>

import java.io.BufferedWriter; import java.io.IOException; import java.nio.charset.StandardCharsets; import java.nio.file.Files; import java.nio.file.Paths; public class WritingUTF8TextFile { public static void main(String[] args) throws IOException { //StandardCharsets is avail...

If you want to see the schema information of your table, you can use one of the following: SHOW CREATE TABLE child; -- Option 1 CREATE TABLE `child` ( `id` int(11) NOT NULL AUTO_INCREMENT, `fullName` varchar(100) NOT NULL, `myParent` int(11) NOT NULL, PRIMARY KEY (`id`), KEY `momm...

In general, it is considered good practice to throw by value (rather than by pointer), but catch by (const) reference. try { // throw new std::runtime_error("Error!"); // Don't do this! // This creates an exception object // on the heap and would require you to catch the ...

Even when all your work is directed at a single worksheet, it's still a very good practice to explicitly specify the worksheet in your code. This habit makes it much easier to expand your code later, or to lift parts (or all) of a Sub or Function to be re-used someplace else. Many developers establi...

Given a file sample: hello world ahello here hello_there A normal grep for "hello" returns: $ grep hello sample hello world ahello here hello_there Using -w allows to select those lines containing matches that form whole words: $ grep -w hello sample hello world

Suppose you have many changes in one or more files but from each file you only want to commit some of the changes, you can select the desired changes using: git add -p or git add -p [file] Each of your changes will be displayed individually, and for each change you will be prompted to choose...

First, ensure you have imported sessions from flask from flask import session To use session, a Flask application needs a defined SECRET_KEY. app = Flask(__name__) app.secret_key = 'app secret key' Sessions are implemented by default using a cookie signed with the secret key. This ensures t...

Modern A weak reference looks like one of these: @property (weak) NSString *property; NSString *__weak variable; If you have a weak reference to an object, then under the hood: You're not retaining it. When it gets deallocated, every reference to it will automatically be set to nil Obje...

A word of caution: AsyncTask has many gotcha's apart from the memory leak described here. So be careful with this API, or avoid it altogether if you don't fully understand the implications. There are many alternatives (Thread, EventBus, RxAndroid, etc). One common mistake with AsyncTask is to c...

The when is a keyword added in C# 6, and it is used for exception filtering. Before the introduction of the when keyword, you could have had one catch clause for each type of exception; with the addition of the keyword, a more fine-grained control is now possible. A when expression is attached to ...

Assuming that you have successfully created a JFrame and that Swing has been imported... You can import Swing entirely import javax.Swing.*; or You can import the Swing Components/Frame that you intend to use import javax.Swing.Jframe; import javax.Swing.JButton; Now down to adding the J...

Leaflet is an open-source JavaScript library for making dynamic maps for the web. RStudio wrote R bindings for Leaflet, available through its leaflet package, built with htmlwidgets. Leaflet maps integrate well with the RMarkdown and Shiny ecosystems. The interface is piped, using a leaflet() funct...

PHP is a loosely typed language. This means that, by default, it doesn't require operands in an expression to be of the same (or compatible) types. For example, you can append a number to a string and expect it to work. var_dump ("This is example number " . 1); The output will be: ...