Tutorial by Examples: di

Difference between ENTRYPOINT and CMD

There are two Dockerfile directives to specify what command to run by default in built images. If you only specify CMD then docker will run that command using the default ENTRYPOINT, which is /bin/sh -c. You can override either or both the entrypoint and/or the command when you start up the built im...

Docker • Building images

Range and addition

Let's take an example of adding a value to a range (as it could be done in a loop for example): 3+1:5 Gives: [1] 4 5 6 7 8 This is because the range operator : has higher precedence than addition operator +. What happens during evaluation is as follows: 3+1:5 3+c(1, 2, 3, 4, 5) expansio...

R Language • Arithmetic Operators

Adding the Doctype

The <!DOCTYPE> declaration should always be included at the top of the HTML document, before the <html> tag. 5 See HTML 5 Doctype for details on the HTML 5 Doctype. <!DOCTYPE html> 4.01 See HTML 4.01 Doctypes for details on how these types differ from each other. Stri...

HTML • Doctypes

Install Yii2 advanced in ubuntu

First we need to install composer. Steps to install composer Install Composer. curl -sS https://getcomposer.org/installer | php Now change directory: sudo mv composer.phar /usr/local/bin/composer Check composer working composer Now Composer installed. There two ways to install Yii2 adv...

yii2 • Getting started with yii2

Arrays union, intersection and difference

x = [5, 5, 1, 3] y = [5, 2, 4, 3] Union (|) contains elements from both arrays, with duplicates removed: x | y => [5, 1, 3, 2, 4] Intersection (&) contains elements which are present both in first and second array: x & y => [5, 3] Difference (-) contains elements which ar...

Ruby Language • Arrays

Build and Install Erlang/OTP on Ubuntu

The following examples show two main methods for installing Erlang/OTP on Ubuntu. Method 1 - Pre-built Binary Package Simply run this command and it will download and install the latest stable Erlang release from Erlang Solutions. $ sudo apt-get install erlang Method 2 - Build and Install from...

Erlang Language • Installation

Integer Division

The standard division symbol (/) operates differently in Python 3 and Python 2 when applied to integers. When dividing an integer by another integer in Python 3, the division operation x / y represents a true division (uses __truediv__ method) and produces a floating point result. Meanwhile, the ...

Python Language • Incompatibilities moving from Python 2 to Python 3

Opening the Visual Basic Editor (VBE)

Step 1: Open a Workbook Step 2 Option A: Press Alt + F11 This is the standard shortcut to open the VBE. Step 2 Option B: Developer Tab --> View Code First, the Developer Tab must be added to the ribbon. Go to File -> Options -> Customize Ribbon, then check the box for developer. ...

excel-vba • Getting started with excel-vba

Difference between single-quoted and double-quoted String literals

The main difference is that double-quoted String literals support string interpolations and the full set of escape sequences. For instance, they can include arbitrary Ruby expressions via interpolation: # Single-quoted strings don't support interpolation puts 'Now is #{Time.now}' # Now is #{Time...

Ruby Language • Strings

Differences between range and xrange functions

In Python 2, range function returns a list while xrange creates a special xrange object, which is an immutable sequence, which unlike other built-in sequence types, doesn't support slicing and has neither index nor count methods: Python 2.x2.3 print(range(1, 10)) # Out: [1, 2, 3, 4, 5, 6, 7, 8, 9...

Python Language • Incompatibilities moving from Python 2 to Python 3

Hello World in C++/CLI

using namespace System; int main(array<String^>^ args) { Console::WriteLine("Hello World"); }

.NET Framework • Getting started with .NET Framework

Extension methods dispatch based on static type

The static (compile-time) type is used rather than the dynamic (run-time type) to match parameters. public class Base { public virtual string GetName() { return "Base"; } } public class Derived : Base { public override string GetName() { ...

C# Language • Extension Methods

MapView: embedding a GoogleMap in an existing layout

It is possible to treat a GoogleMap as an Android view if we make use of the provided MapView class. Its usage is very similar to MapFragment. In your layout use MapView as follows: <com.google.android.gms.maps.MapView xmlns:android="http://schemas.android.com/apk/res/android" ...

Android • Google Maps API v2 for Android

Create a new Rails app with your choice of database and including the RSpec Testing Tool

Rails uses sqlite3 as the default database, but you can generate a new rails application with a database of your choice. Just add the -d option followed by the name of the database. $ rails new MyApp -T -d postgresql This is a (non-exhaustive) list of available database options: mysql oracle...

Ruby on Rails • Getting started with Ruby on Rails

Overwrite single file in current working directory with the same from another branch

The checked out file will overwrite not yet commited changes you did in this file. This command will check out the file file.example (which is located in the directory path/to/) and overwrite any changes you might have made to this file. git checkout some-branch path/to/file some-branch can be ...

Git • Branching

Reading words from an entire file

In Haskell, it often makes sense not to bother with file handles at all, but simply read or write an entire file straight from disk to memory†, and do all the partitioning/processing of the text with the pure string data structure. This avoids mixing IO and program logic, which can greatly help avoi...

Haskell Language • IO

Detect what debian-based distribution you are working in

Just execute lsb_release -a. On Debian: $ lsb_release -a No LSB modules are available. Distributor ID: Debian Description: Debian GNU/Linux testing (stretch) Release: testing Codename: stretch On Ubuntu: $ lsb_release -a No LSB modules are available. Distributor ID: Ubun...

GNU/Linux • Detecting Linux distribution name and version

Creating using dictionaryWithObjectsAndKeys:

NSDictionary *inventory = [NSDictionary dictionaryWithObjectsAndKeys: [NSNumber numberWithInt:13], @"Mercedes-Benz SLK250", [NSNumber numberWithInt:22], @"Mercedes-Benz E350", [NSNumber numberWithInt:19], @"BMW M3 Coupe", [NSNumber numberWithInt:16],...

Objective-C Language • NSDictionary

Access Modifiers

The Dim statement should be reserved for local variables. At module-level, prefer explicit access modifiers: Private for private fields, which can only be accessed within the module they're declared in. Public for public fields and global variables, which can be accessed by any calling code. Fr...

VBA • Declaring Variables

Accessing the Visual Basic Editor in Microsoft Office

You can open the VB editor in any of the Microsoft Office applications by pressing Alt+F11 or going to the Developer tab and clicking on the "Visual Basic" button. If you don't see the Developer tab in the Ribbon, check if this is enabled. By default the Developer tab is disabled. To enab...

VBA • Getting started with VBA