Tutorial by Examples: t

Selecting with table alias

SELECT e.Fname, e.LName FROM Employees e The Employees table is given the alias 'e' directly after the table name. This helps remove ambiguity in scenarios where multiple tables have the same field name and you need to be specific as to which table you want to return data from. SELECT e.Fname,...

SQL • SELECT

Use the `email` as username and get rid of the `username` field

If you want to get rid of the username field and use email as unique user identifier, you will have to create a custom User model extending AbstractBaseUser instead of AbstractUser. Indeed, username and email are defined in AbstractUser and you can't override them. This means you will also have to r...

Django • Extending or Substituting User Model

Basic Setup

Backbone requires Underscore and (optionally) jQuery - for DOM manipulation (using Backbone.View) and RESTful persistence. The quickest way to get up and running with Backbone is to create an index.html file with simple script tags in the HTML <head>: <html> <head> ...

backbone.js • Getting started with backbone.js

CREATE TABLE With FOREIGN KEY

Below you could find the table Employees with a reference to the table Cities. CREATE TABLE Cities( CityID INT IDENTITY(1,1) NOT NULL, Name VARCHAR(20) NOT NULL, Zip VARCHAR(10) NOT NULL ); CREATE TABLE Employees( EmployeeID INT IDENTITY (1,1) NOT NULL, FirstName VARCHA...

SQL • CREATE TABLE

Parsing dates when reading from csv

You can specify a column that contains dates so pandas would automatically parse them when reading from the csv pandas.read_csv('data_file.csv', parse_dates=['date_column'])

pandas • Pandas IO tools (reading and saving data sets)

Recursive functions

A recursive function is a function that calls itself in its definition. For example the mathematical function, factorial, defined by factorial(n) = n*(n-1)*(n-2)*...*3*2*1. can be programmed as def factorial(n): #n here should be an integer if n == 0: return 1 else: ...

Python Language • Functions

static

The static modifier is used to declare a static member, which does not need to be instantiated in order to be accessed, but instead is accessed simply through its name, i.e. DateTime.Now. static can be used with classes, fields, methods, properties, operators, events, and constructors. While an in...

C# Language • Keywords

Binary operators with assignment

C# has several operators that can be combined with an = sign to evaluate the result of the operator and then assign the result to the original variable. Example: x += y is the same as x = x + y Assignment operators: += -= *= /= %= &= |= ^= <<= >>=

C# Language • Operators

Sending a minimal HTTP request manually using Telnet

This example demonstrates that HTTP is a text-based Internet communications protocol, and shows a basic HTTP request and the corresponding HTTP response. You can use Telnet to manually send a minimal HTTP request from the command line, as follows. Start a Telnet session to the web server www.e...

HTTP • HTTP requests

HTTP Analytics through an Event Emitter

In the HTTP server code (e.g. server.js): const EventEmitter = require('events') const serverEvents = new EventEmitter() // Set up an HTTP server const http = require('http') const httpServer = http.createServer((request, response) => { // Handler the request... // Then emit an event...

Node.js • Event Emitters

Flash Develop Installation

FlashDevelop is a multi-platform open source IDE created in 2005 for Flash developers. With no cost, it's a very popular way to get started developing with AS3. To Install FlashDevelop: Download The Installation File and run the installer Once installation is complete, run FlashDevelop. On the ...

ActionScript 3 • Getting started with ActionScript 3

Apache Flex Installation

from http://flex.apache.org/doc-getstarted.html Download the SDK installer Run the SDK installer. The first question you will be asked is the installation directory. on a Mac, use /Applications/Adobe Flash Builder 4.7/sdks/4.14.0/ on a PC, use C:\Program Files(x86)\Adobe Flash Builder ...

ActionScript 3 • Getting started with ActionScript 3

What is Selenium WebDriver ?

Selenium is a set of tools designed to automate browsers. It is commonly used for web application tests across multiple platforms. There are a few tools available under the Selenium umbrella, such as Selenium WebDriver(ex-Selenium RC), Selenium IDE and Selenium Grid. WebDriver is a remote control i...

selenium-webdriver • Getting started with selenium-webdriver

Create a string with strikethrough text

Objective-C NSMutableAttributedString *attributeString = [[NSMutableAttributedString alloc] initWithString:@"Your String here"]; [attributeString addAttribute:NSStrikethroughStyleAttributeName value:@2 range:NSMakeRange(0, [attributeString length...

iOS • NSAttributedString

Installation or Setup

AEM can be installed as a standalone executable JAR file or through web application servers, such as JBoss and WebSphere, as a WAR file. Prerequisites AEM 6.2 needs at minimum the following in order to run Java Runtime Environment (JRE) 1.8x (64bit) 5GB of free disk space for installation 2GB...

aem • Getting started with aem

Multiple Line

/* This is a CSS comment */ div { color: red; }

CSS • Comments

Working with null-string when parsing json

{ "some_string": null, "ather_string": "something" } If we will use this way: JSONObject json = new JSONObject(jsonStr); String someString = json.optString("some_string"); We will have output: someString = "null"; So we need to...

Android • JSON in Android with org.json

Installation or Setup

Detailed instructions on getting braintree set up or installed.

braintree • Getting started with braintree

Basic VectorDrawable

A VectorDrawable should consist of at least one <path> tag defining a shape <vector xmlns:android="http://schemas.android.com/apk/res/android" android:width="24dp" android:height="24dp" android:viewportWidth="24.0" android:viewpor...

Android • VectorDrawable and AnimatedVectorDrawable

Using

A <clip-path> defines a shape which acts as a window, only allowing parts of a <path> to show if they are within the <clip-path> shape and cutting off the rest. <vector xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.an...

Android • VectorDrawable and AnimatedVectorDrawable