Tutorial by Examples: g

Install node modules npm install express npm install socket.io Node.js server const express = require('express'); const app = express(); const server = app.listen(3000,console.log("Socket.io Hello World server started!")); const io = require('socket.io')(server); io.on('connec...

When an object is exposed to the template context, its arguments-less methods are available. This is useful when these functions are "getters". But it can be hazardeous if these methods alter some data or have some side effects. Eventhough you likely trust the template writer, he may not b...

Classes have a local scope during definition, but functions inside the class do not use that scope when looking up names. Because lambdas are functions, and comprehensions are implemented using function scope, this can lead to some surprising behavior. a = 'global' class Fred: a = 'class' ...

$> pwd /home/myUserHome $> cd .. $> pwd /home will print the current path to the console.

Basic assembly support with gcc has the following syntax: asm [ volatile ] ( AssemblerInstructions ) where AssemblerInstructions is the direct assembly code for the given processor. The volatile keyword is optional and has no effect as gcc does not optimize code within a basic asm statement. A...

Extended asm support in gcc has the following syntax: asm [volatile] ( AssemblerTemplate : OutputOperands [ : InputOperands [ : Clobbers ] ]) asm [volatile] goto ( AssemblerTemplate : : Inp...

When working with large files, you can use the System.IO.File.ReadLines method to read all lines from a file into an IEnumerable<string>. This is similar to System.IO.File.ReadAllLines, except that it doesn't load the whole file into memory at once, making it more efficient when working with l...

Ada 2012(TC-1) with Ada.Text_IO; procedure Main is type Some_Float digits 8 range 0.0 .. 10.0; X : Some_Float := 2.71; begin Ada.Text_IO.Put_Line (X'Image); end Main; Result 2.71000E+00

Ada 2012(TC-1) with Ada.Text_IO; procedure Main is type Some_Integer is range -42 .. 42; X : Some_Integer := 17; begin Ada.Text_IO.Put_Line (X'Image); end Main; Result 17

Ada 2012(TC-1) with Ada.Text_IO; procedure Main is type Fruit is (Banana, Orange, Pear); X : Fruit := Orange; begin Ada.Text_IO.Put_Line (X'Image); Ada.Text_IO.Put_Line (Pear'Image); end Main; Result ORANGE PEAR

Well, if you want a switch/case construct, the most straightforward way to go is to use the good old if/else construct: def switch(value): if value == 1: return "one" if value == 2: return "two" if value == 42: return "the answer to...

Another way, which is very readable and elegant, but far less efficient than a if/else structure, is to build a class such as follows, that will read and store the value to compare with, expose itself within the context as a callable that will return true if it matches the stored value: class Switc...

It might be easier if you think of GROUP BY as "for each" for the sake of explanation. The query below: SELECT EmpID, SUM (MonthlySalary) FROM Employee GROUP BY EmpID is saying: "Give me the sum of MonthlySalary's for each EmpID" So if your table looked like this: +----...

Pre-processing in caret is done through the preProcess() function. Given a matrix or data frame type object x, preProcess() applies transformations on the training data which can then be applied to testing data. The heart of the preProcess() function is the method argument. Method operations are ap...

It is possible to perform ViewActions on a view using the perform method. The ViewActions class provides helper methods for the most common actions, like: ViewActions.click() ViewActions.typeText() ViewActions.clearText() For example, to click on the view: onView(...).perform(click()); onVi...

With the ViewMatchers you can find view in the current view hierarchy. To find a view, use the onView() method with a view matcher which selects the correct view. The onView() methods return an object of type ViewInteraction. For example, finding a view by its R.id is as simple as: onView(withId(...

Classes are vital aspects of OOP. A class is like the "blueprint" of an object. An object has the properties of a class, but the characteristics are not defined within the class itself. As each object can be different, they define their own characteristics. Public Class Person End Class ...

Overloading is the creation of more than one procedure, instance constructor, or property in a class with the same name but different argument types. Class Person Overloads Sub Display(ByVal theChar As Char) ' Add code that displays Char data. End Sub Overloads Sub Display...

In C, character constants and string literals are different things. A character surrounded by single quotes like 'a' is a character constant. A character constant is an integer whose value is the character code that stands for the character. How to interpret character constants with multiple charac...

To know the path of the directory your file is in you can use: Esc to enter command mode :pwd This will print the path to the directory at the bottom of the editor, like this I'm a ninja ~ ~ ~ ~ ~ /home/ubuntu/myfolder 1,5 All Now...