The Arbitrary class is for types that can be randomly generated by QuickCheck.
The minimal implementation of Arbitrary is the arbitrary method, which runs in the Gen monad to produce a random value.
Here is an instance of Arbitrary for the following datatype of non-empty lists.
import Test.QuickC...
% Define serial port with a baud rate of 115200
rate = 115200;
if ispc
s = serial('COM1', 'BaudRate',rate);
elseif ismac
% Note that on OSX the serial device is uniquely enumerated. You will
% have to look at /dev/tty.* to discover the exact signature of your
% serial device
...
Assuming you created the serial port object s as in this example, then
% Read one byte
data = fread(s, 1);
% Read all the bytes, version 1
data = fread(s);
% Read all the bytes, version 2
data = fread(s, s.BytesAvailable);
% Close the serial port
fclose(s);
Assuming you created the serial port object s as in this example, then to close it
fclose(s)
However, sometimes you can accidentally lose the port (e.g. clear, overwrite, change scope, etc...), and fclose(s) will no longer work. The solution is easy
fclose(instrfindall)
More info at instrfin...
Assuming you created the serial port object s as in this example, then
% Write one byte
fwrite(s, 255);
% Write one 16-bit signed integer
fwrite(s, 32767, 'int16');
% Write an array of unsigned 8-bit integers
fwrite(s,[48 49 50],'uchar');
% Close the serial port
fclose(s);
As there is currently no simple way of combining dictionaries in Swift, it can be useful to overload the + and += operators in order to add this functionality using generics.
// Combines two dictionaries together. If both dictionaries contain
// the same key, the value of the right hand side dicti...
The SQL 2008 standard defines the FETCH FIRST clause to limit the number of records returned.
SELECT Id, ProductName, UnitPrice, Package
FROM Product
ORDER BY UnitPrice DESC
FETCH FIRST 10 ROWS ONLY
This standard is only supported in recent versions of some RDMSs. Vendor-specific non-stand...
Pojo Model
public class Model {
private String firstName;
private String lastName;
private int age;
/* Getters and setters not shown for brevity */
}
Example: String to Object
Model outputObject = objectMapper.readValue(
"{\"firstName\":\"J...
It's possible to attach an object to an existing object as if there was a new property. This is called association and allows one to extend existing objects. It can be used to provide storage when adding a property via a class extension or otherwise add additional information to an existing object.
...
You can use the <img> or <object> elements to embed external SVG elements. Setting the height and width is optional but is highly recommended.
Using the image element
<img src="attention.svg" width="50" height="50">
Using <img> does not allo...
<link rel="alternate stylesheet" href="path/to/style.css" title="yourTitle">
Some browsers allow alternate style sheets to apply if they are offered. By default they will not be applied, but usually they can be changed through the browser settings:
Firefox l...
Unlike classes, structures cannot inherit:
class MyView: NSView { } // works
struct MyInt: Int { } // error: inheritance from non-protocol type 'Int'
Structures, however, can adopt protocols:
struct Vector: Hashable { ... } // works
Composer tracks which versions of packages you have installed in a file called composer.lock, which is intended to be committed to version control, so that when the project is cloned in the future, simply running composer install will download and install all the project's dependencies.
Composer de...
The operator for an "exclusive or" (for short XOR) is: ^
This operator returns true when one, but only one, of the supplied bools are true.
true ^ false // Returns true
false ^ true // Returns true
false ^ false // Returns false
true ^ true // Returns false
It is possible to bind values to names using @:
struct Badger {
pub age: u8
}
fn main() {
// Let's create a Badger instances
let badger_john = Badger { age: 8 };
// Now try to find out what John's favourite activity is, based on his age
match badger_john.age {
...
// Create a boolean value
let a = true;
// The following expression will try and find a pattern for our value starting with
// the topmost pattern.
// This is an exhaustive match expression because it checks for every possible value
match a {
true => println!("a is true"),
...
It's possible to treat multiple, distinct values the same way, using |:
enum Colour {
Red,
Green,
Blue,
Cyan,
Magenta,
Yellow,
Black
}
enum ColourModel {
RGB,
CMYK
}
// let's take an example colour
let colour = Colour::Red;
let model = match ...
Patterns can be matched based on values independent to the value being matched using if guards:
// Let's imagine a simplistic web app with the following pages:
enum Page {
Login,
Logout,
About,
Admin
}
// We are authenticated
let is_authenticated = true;
// But we aren't admins...
// View to hold the CAGradientLayer.
let view: UIView = UIView(frame: CGRect(x: 0, y: 0, width: 320, height: 320))
// Initialize gradient layer.
let gradientLayer: CAGradientLayer = CAGradientLayer()
// Set frame of gradient layer.
gradientLayer.frame = view.bounds
// Color at...
By default the Python random module use the Mersenne Twister PRNG to generate random numbers, which, although suitable in domains like simulations, fails to meet security requirements in more demanding environments.
In order to create a cryptographically secure pseudorandom number, one can use Syst...
