Tutorial by Examples: er

Complex Example - jQuery UI Dynamicly Create Dialog

Generally, dialog relies on a div within the HTML. Sometimes you may want to create a dialog from scratch, programmatically. Here is an example of a complex modal dialog created dynamically with interactive functions. HTML <div id="users-contain" class="ui-widget"> &lt...

jQuery UI Library • Dialog

Overview

Redis is an in-memory remote database that offers high performance, replication, and a unique data model to produce a platform for solving problems. Redis is an open source (BSD licensed), in-memory data structure , used as database, cache and message broker. It is categorized as a NoSQL key-value s...

redis • Getting started with redis

Use requestAnimationFrame to fade in element

View jsFiddle: https://jsfiddle.net/HimmatChahal/jb5trg67/ Copy + Pasteable code below: <html> <body> <h1>This will fade in at 60 frames per second (or as close to possible as your hardware allows)</h1> <script> // Fad...

JavaScript • requestAnimationFrame

Member initialization

Each of the enum members may be initialized with a value. If a value is not specified for a member, by default it's initialized to 0 (if it's the first member in the member list) or to a value greater by 1 than the value of the preceding member. Module Module1 Enum Size Small ...

Visual Basic .NET Language • Enum

Builder Pattern / C# / Fluent Interrface

public class Email { public string To { get; set; } public string From { get; set; } public string Subject { get; set; } public string Body { get; set; } } public class EmailBuilder { private readonly Email _email; public EmailBuilder() { _email = ...

Design patterns • Builder Pattern

Devise Controller Filters & Helpers

To set up a controller with user authentication using devise, add this before_action: (assuming your devise model is 'User'): before_action :authenticate_user! To verify if a user is signed in, use the following helper: user_signed_in? For the current signed-in user, use this helper: current_us...

Ruby on Rails • User Authentication in Rails

Bitwise operators

Bitwise operators perform operations on bit values of data. These operators convert operands to signed 32-bit integers in two's complement. Conversion to 32-bit integers Numbers with more than 32 bits discard their most significant bits. For example, the following integer with more than 32 bits i...

JavaScript • Bitwise operators

Reading or writing through a null pointer

int *ptr = nullptr; *ptr = 1; // Undefined behavior This is undefined behavior, because a null pointer does not point to any valid object, so there is no object at *ptr to write to. Although this most often causes a segmentation fault, it is undefined and anything can happen.

C++ • Undefined Behavior

Modifying a string literal

C++11 char *str = "hello world"; str[0] = 'H'; "hello world" is a string literal, so modifying it gives undefined behaviour. The initialisation of str in the above example was formally deprecated (scheduled for removal from a future version of the standard) in C++03. A num...

C++ • Undefined Behavior

Switch off properties during macro execution

It is best practice in any programming language to avoid premature optimization. However, if testing reveals that your code is running too slowly, you may gain some speed by switching off some of the application’s properties while it runs. Add this code to a standard module: Public Sub SpeedUp( _ ...

excel-vba • VBA Best Practices

Pattern matching on a map

%{username: username} = %{username: "John Doe", id: 1} # username == "John Doe" %{username: username, id: 2} = %{username: "John Doe", id: 1} ** (MatchError) no match of right hand side value: %{id: 1, username: "John Doe"}

Elixir Language • Pattern matching

Rename Folders

To rename a folder from oldName to newName git mv directoryToFolder/oldName directoryToFolder/newName Followed by git commit and/or git push If this error occurs: fatal: renaming 'directoryToFolder/oldName' failed: Invalid argument Use the following command: git mv directoryToFolder/oldN...

Git • Renaming

Sorting sequence containers by overloaded less operator

If no ordering function is passed, std::sort will order the elements by calling operator< on pairs of elements, which must return a type contextually convertible to bool (or just bool). Basic types (integers, floats, pointers etc) have already build in comparison operators. We can overload this ...

C++ • Sorting

Sorting sequence containers using compare function

// Include sequence containers #include <vector> #include <deque> #include <list> // Insert sorting algorithm #include <algorithm> class Base { public: // Constructor that set variable to the value of v Base(int v): variable(v) { } i...

C++ • Sorting

Sorting sequence containers using lambda expressions (C++11)

C++11 // Include sequence containers #include <vector> #include <deque> #include <list> #include <array> #include <forward_list> // Include sorting algorithm #include <algorithm> class Base { public: // Constructor that set variable to the va...

C++ • Sorting

BigInteger Mathematical Operations Examples

BigInteger is in an immutable object, so you need to assign the results of any mathematical operation, to a new BigInteger instance. Addition: 10 + 10 = 20 BigInteger value1 = new BigInteger("10"); BigInteger value2 = new BigInteger("10"); BigInteger sum = value1.add(value...

Java Language • BigInteger

select_related for all queries

Model with ForeignKey We will work with these models : from django.db import models class Book(models.Model): name= models.CharField(max_length=50) author = models.ForeignKey(Author) class Author(models.Model): name = models.CharField(max_length=50) Suppose we often (always) access ...

Django • Custom Managers and Querysets

Object properties iteration

You can access each property that belongs to an object with this loop for (var property in object) { // always check if an object has a property if (object.hasOwnProperty(property)) { // do stuff } } You should include the additional check for hasOwnProperty because an o...

JavaScript • Objects

What are properties?

Here is an example class which has a couple of instance variables, without using properties: @interface TestClass : NSObject { NSString *_someString; int _someInt; } -(NSString *)someString; -(void)setSomeString:(NSString *)newString; -(int)someInt; -(void)setSomeInt:(NSString *)...

Objective-C Language • Properties

Custom getters and setters

The default property getters and setters can be overridden: @interface TestClass @property NSString *someString; @end @implementation TestClass // override the setter to print a message - (void)setSomeString:(NSString *)newString { NSLog(@"Setting someString to %@", newS...

Objective-C Language • Properties