Tutorial by Examples: t

NuGet version Before you start: make sure your NuGet version is up to date. In Visual Studio, go to Tools > Extensions and Updates, then Updates > Visual Studio Gallery. Check if there is a NuGet Update available and install it. Or, you can uninstall the existing nuget and reinstall it. It w...

SilverStripe can be installed via composer or through the extraction of downloaded zip file. To install through composer we run the following command composer create-project silverstripe/installer /path/to/project 3.4.0 A download zip file can be found on the download page of the SilverStripe w...

It is possible to detect whether an operator or function can be called on a type. To test if a class has an overload of std::hash, one can do this: #include <functional> // for std::hash #include <type_traits> // for std::false_type and std::true_type #include <utility> // for s...

where clauses can be negated using the where.not syntax: class Person < ApplicationRecord #attribute :first_name, :string end people = Person.where.not(first_name: ['Mark', 'Mary']) # => SELECT "people".* FROM "people" WHERE "people"."first_name&quot...

You can validate any object, even plain ruby. class User include ActiveModel::Validations attr_reader :name, :age def initialize(name, age) @name = name @age = age end validates :name, presence: true validates :age, numericality: { only_integer: true, greater_than...

If you want to support a url parameter more complex than an id number, you may run into trouble with the parser if the value contains a period. Anything following a period will be assumed to be a format (i.e. json, xml). You can work around this limitation by using a constraint to broaden the accep...

Swift func createCollectionView() { let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout() let collectionView = UICollectionView(frame: CGRect(x: 0, y: 0, width: view.frame.width, height: view.frame.height), collectionViewLayout: layout) collectionView.dataSource = sel...

// MARK: - UICollectionViewDelegateFlowLayout extension ViewController: UICollectionViewDelegateFlowLayout { func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize { return ...

As Rails follows the MVC pattern Views are where your "templates" are for your actions. Let's say you have a controller articles_controller.rb. For this controller you would have a folder in views called app/views/articles: app |-- controllers | '-- articles_controller.rb | '-- vie...

You can use an initializer to set default property values: struct Example { var upvotes: Int init() { upvotes = 42 } } let myExample = Example() // call the initializer print(myExample.upvotes) // prints: 42 Or, specify default property values as a part of the property...

struct MetricDistance { var distanceInMeters: Double init(fromCentimeters centimeters: Double) { distanceInMeters = centimeters / 100 } init(fromKilometers kilos: Double) { distanceInMeters = kilos * 1000 } } let myDistance = MetricDistance(fromCentim...

The Number constructor has some built in constants that can be useful Number.MAX_VALUE; // 1.7976931348623157e+308 Number.MAX_SAFE_INTEGER; // 9007199254740991 Number.MIN_VALUE; // 5e-324 Number.MIN_SAFE_INTEGER; // -9007199254740991 Number.EPSILON; // 0.000...

open my $fh, '<', $filename or die "Could not open $filename for reading: $!"; my $contents = do { local $/; <$fh> }; After opening the file (read man perlio if you want to read specific file encodings instead of raw bytes), the trick is in the do block: <$fh>, the ...

Using the idiom from The Manual Way several times in a script soon gets tedious so you might want to try a module. use Path::Tiny; my $contents = path($filename)->slurp; You can pass a binmode option if you need control over file encodings, line endings etc. - see man perlio: my $contents =...

With the use of the extends keyword among classes, all the properties of the superclass (also known as the Parent Class or Base Class) are present in the subclass (also known as the Child Class or Derived Class) public class BaseClass { public void baseMethod(){ System.out.println(&...

To install the latest version of a package named SomePackage: $ pip install SomePackage To install a specific version of a package: $ pip install SomePackage==1.0.4 To specify a minimum version to install for a package: $ pip install SomePackage>=1.0.4 If commands shows permission den...

To uninstall a package: $ pip uninstall SomePackage

To list installed packages: $ pip list # example output docutils (0.9.1) Jinja2 (2.6) Pygments (1.5) Sphinx (1.1.2) To list outdated packages, and show the latest version available: $ pip list --outdated # example output docutils (Current: 0.9.1 Latest: 0.10) Sphinx (Current: 1.1.2 Late...

Euler angles are "degree angles" like 90, 180, 45, 30 degrees. Quaternions differ from Euler angles in that they represent a point on a Unit Sphere (the radius is 1 unit). You can think of this sphere as a 3D version of the Unit circle you learn in trigonometry. Quaternions differ from Eu...

Quaternion.LookRotation(Vector3 forward [, Vector3 up]) will create a Quaternion rotation that looks forward 'down' the forward vector and has the Y axis aligned with the 'up' vector. If the up vector is not specified, Vector3.up will be used. Rotate this Game Object to look at a target Game Object...