Tutorial by Examples: f

The package clause is not directly binded with the file where it is found. It is possible to find common elements of the package clause in diferent files. For example, the package clauses bellow can be found in the file math1.scala and in the file math2.scala. File math1.scala package org { ...

Xcode have ability to run any script with hotkey. Here is example how to assign hotkey ⌘+⌥+⌃+⇧+T to open Terminal app in current project folder. Create bash script and save it in some folder #!/bin/bash # Project Name: $XcodeProject # Project Dir: $XcodeProjectPath # Workspace Dir: $X...

Data is usually perceived as something static that is entered into a database and later queried. But in many environments, data is actually more similar to a product in an assembly line, moving from one environment to another and undergoing transformations along the way. ■ OLTP: online transactio...

While developing, inserting the following line to your code: assert False, value will cause django to raise an AssertionError with the value supplied as an error message when this line is executed. If this occurs in a view, or in any code called from a view, and DEBUG=True is set, a full and de...

Debugging takes time and effort. Instead of chasing bugs with a debugger, consider spending more time on making your code better by: Write and run Tests. Python and Django have great builtin testing frameworks - that can be used to test your code much faster than manually with a debugger. Writ...

Binary Literals: The integral types (byte, short, int, and long) can also be expressed using the binary number system. To specify a binary literal, add the prefix 0b or 0B to the number. Strings in switch Statements: You can use a String object in the expression of a switch statement The try-wit...

Lambda Expressions, a new language feature, has been introduced in this release. They enable you to treat functionality as a method argument, or code as data. Lambda expressions let you express instances of single-method interfaces (referred to as functional interfaces) more compactly. Method r...

Nested if()...else statements take more execution time (they are slower) in comparison to an if()...else ladder because the nested if()...else statements check all the inner conditional statements once the outer conditional if() statement is satisfied, whereas the if()..else ladder will stop condit...

The very first line in each of your LaTeX programs should do this. It should follow the form \documentclass{...}. What you put within the curly braces is very important. Some document classes give you extra commands to use, others use a different format, and all have specific parameters you can inp...

Using bash you can easily locate a file with the locate command. For example say you are looking for the file mykey.pem: locate mykey.pem Sometimes files have strange names for example you might have a file like random7897_mykey_0fidw.pem. Let's say you're looking for this file but you only reme...

// plugin initialization $.fn.greenify = function() { // within the function you can use any of the jQuery methods // and `this` context refers to jQuery object this.css( "color", "green" ); }; // apply plugin $( "a" ).greenify();

When a class needs to be provided with hard dependencies best practice is to use a constructor injection pattern where those dependencies are injected using a factory. Let's assume that MyClass is hard dependent on a value $dependency that needs to be resolved from the application config. <?php...

One common pitfall is to try and use this in a nested function or an object, where the context has been lost. document.getElementById('myAJAXButton').onclick = function(){ makeAJAXRequest(function(result){ if (result) { // success this.className = 'success'; } }) }...

5.1 Every function has a bind method, which will create a wrapped function that will call it with the correct context. See here for more information. var monitor = { threshold: 5, check: function(value) { if (value > this.threshold) { this.display("Value is too high!&quot...

When using a function as a constructor, it has a special this binding, which refers to the newly created object: function Cat(name) { this.name = name; this.sound = "Meow"; } var cat = new Cat("Tom"); // is a Cat object cat.sound; // Returns "Meow" var ca...

import React, { Component } from 'react'; type Props = { posts: Array<Article>, dispatch: Function, children: ReactElement } class Posts extends Component { props: Props; render () { // rest of the code goes here } }

The reference to the outer class uses the class name and this public class OuterClass { public class InnerClass { public void method() { System.out.println("I can access my enclosing class: " + OuterClass.this); } } } You can access fields and ...

Elements of String are characters that can be accessed by the indexing operation string[index]. val str = "Hello, World!" println(str[1]) // Prints e String elements can be iterated with a for-loop. for (c in str) { println(c) }

You can make your plugin customizable by accepting options. $.fn.colourize = function(options) { // This is one method to support default options var style = $.extend({ color: "green", backgroundColor: "white" }, options); // Set the col...

You can delete trailing spaces with the following command. :%s/\s\+$//e This command is explained as follows: enter Command mode with : do this to the entire file with % (default would be for the current line) substitute action s / start of the search pattern \s whitespace character \+ e...