Tutorial by Examples: e

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 ...

Swift Ctrl + Drag from the UItextfield in MainStoryboard to the ViewController Class and create a UITextField Outlet After that select the UItextField again and Ctrl+drag in ViewController class but this time select Action connection and on storage select Did End On Exit then click connect. ...

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 ...

This is a minimalist module that only slurps files into variables, nothing else. use File::Slurper 'read_text'; my $contents = read_text($filename); read_text() takes two optional parameters to specify the file encoding and whether line endings should be translated between the unixish LF or DOS...

Don't use it. Although it has been around for a long time and is still the module most programmers will suggest, it is broken and not likely to be fixed.

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(&...

A generic class with the type parameter Type class MyGenericClass<Type>{ var value: Type init(value: Type){ self.value = value } func getValue() -> Type{ return self.value } func setValue(value: Type){ self.value = value }...

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...

Running $ pip install --upgrade SomePackage will upgrade package SomePackage and all its dependencies. Also, pip automatically removes older version of the package before upgrade. To upgrade pip itself, do $ pip install --upgrade pip on Unix or $ python -m pip install --upgrade pip on ...

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...

When adding indented code blocks inside a list you first need a blank line, then to indent the code further. Different flavours of Markdown have different rules for this. StackExchange requires code to be indented by 8 characters instead of the usual 4. (Spaces replaced with * for clarity): 1...