Tutorial by Examples: g

Getting and setting elements

Use .get(key) to get value by key and .set(key, value) to assign a value to a key. If the element with the specified key doesn't exist in the map, .get() returns undefined. .set() method returns the map object, so you can chain .set() calls. const map = new Map(); console.log(map.get(1)); // und...

JavaScript • Map

Getting the number of elements of a Map

To get the numbers of elements of a Map, use the .size property: const map = new Map([[1, 2], [3, 4]]); console.log(map.size); // 2

JavaScript • Map

Setting state Added of a single entity

EntityState.Added can be set in two fully equivalent ways: By setting the state of its entry in the context: context.Entry(entity).State = EntityState.Added; By adding it to a DbSet of the context: context.Entities.Add(entity); When calling SaveChanges, the entity will be inse...

Entity Framework • Managing entity state

Shrink the code with ProGuard

To enable code shrinking with ProGuard, add minifyEnabled true to the appropriate build type in your build.gradle file. android { buildTypes { release { minifyEnabled true proguardFiles getDefaultProguardFile(‘proguard-android.txt'), 'pro...

android-gradle • Shrink Code and Resources

Setting state Added of an object graph

Setting the state of an object graph (a collection of related entities) to Added is different than setting a single entity as Added (see this example). In the example, we store planets and their moons: Class model public class Planet { public Planet() { Moons = new HashSet<...

Entity Framework • Managing entity state

Set frame rate using requestAnimationFrame

Using requestAnimationFrame may on some systems update at more frames per second than the 60fps. 60fps is the default rate if the rendering can keep up. Some systems will run at 120fps maybe more. If you use the following method you should only use frame rates that are integer divisions of 60 so th...

html5-canvas • Animation

delegate

Delegates are types that represent a reference to a method. They are used for passing methods as arguments to other methods. Delegates can hold static methods, instance methods, anonymous methods, or lambda expressions. class DelegateExample { public void Run() { //using class ...

C# Language • Keywords

Linking projects for faster debugging and development

Building project dependencies can sometimes be a tedious task. Instead of publishing a package version to NPM and installing the dependency to test the changes, use npm link. npm link creates a symlink so the latest code can be tested in a local environment. This makes testing global tools and proje...

Node.js • npm

Locating comments

To locate comments in BeautifulSoup, use the text (or string in the recent versions) argument checking the type to be Comment: from bs4 import BeautifulSoup from bs4 import Comment data = """ <html> <body> <div> <!-- desired text --&gt...

beautifulsoup • Locating elements

The %timeit and `%time` magics

The %timeit magic runs the given code many times, then returns the speed of the fastest result. In [1]: %timeit sum(range(100000)) 100 loops, best of 3: 2.91 ms per loop The %%timeit cell magic can be used to time blocks of code. In [2]: %%timeit ...: a = 0 ...: for i in range(100000):...

ipython • Magics

The Other Looping Constructs: while and repeat

R provides two additional looping constructs, while and repeat, which are typically used in situations where the number of iterations required is indeterminate. The while loop The general form of a while loop is as follows, while (condition) { ## do something ## in loop body } whe...

R Language • Control flow structures

Reading/Writing Data Using System.IO.File

First, let's see three different ways of extracting data from a file. string fileText = File.ReadAllText(file); string[] fileLines = File.ReadAllLines(file); byte[] fileBytes = File.ReadAllBytes(file); On the first line, we read all the data in the file as a string. On the second line, we r...

.NET Framework • System.IO

Serial Ports using System.IO.SerialPorts

Iterating over connected serial ports using System.IO.Ports; string[] ports = SerialPort.GetPortNames(); for (int i = 0; i < ports.Length; i++) { Console.WriteLine(ports[i]); } Instantiating a System.IO.SerialPort object using System.IO.Ports; SerialPort port = new SerialPort(); ...

.NET Framework • System.IO

Override Equals and GetHashCode on custom types

For a class Person like: public class Person { public string Name { get; set; } public int Age { get; set; } public string Clothes { get; set; } } var person1 = new Person { Name = "Jon", Age = 20, Clothes = "some clothes" }; var person2 = new Person { Name ...

C# Language • Equals and GetHashCode

Equals and GetHashCode in IEqualityComparator

For given type Person: public class Person { public string Name { get; set; } public int Age { get; set; } public string Clothes { get; set; } } List<Person> persons = new List<Person> { new Person{ Name = "Jon", Age = 20, Clothes = "some clothes...

C# Language • Equals and GetHashCode

Character Strings

char varchar text

Microsoft SQL Server • Data Types

Unicode Character Strings

nchar nvarchar ntext

Microsoft SQL Server • Data Types

Binary Strings

binary varbinary image

Microsoft SQL Server • Data Types

Rendering text along an arc.

This example shows how to render text along an arc. It includes how you can add functionality to the CanvasRenderingContext2D by extending its prototype. This examples is derived from the stackoverflow answer Circular Text. Example rendering Example code The example adds 3 new text renderi...

html5-canvas • Text

DML Triggers

DML Triggers are fired as a response to dml statements (insert, update or delete). A dml trigger can be created to address one or more dml events for a single table or view. This means that a single dml trigger can handle inserting, updating and deleting records from a specific table or view, but ...

Microsoft SQL Server • Trigger