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Access the nth element of a list (zero-based): list = [1 .. 10] firstElement = list !! 0 -- 1 Note that !! is a partial function, so certain inputs produce errors: list !! (-1) -- *** Exception: Prelude.!!: negative index list !! 1000 -- *** Exception: Prelude.!!: inde...

To make artisan migrate a fresh database before running tests, use DatabaseMigrations. Also if you want to avoid middleware like Auth, use WithoutMiddleware. <?php use Illuminate\Foundation\Testing\WithoutMiddleware; use Illuminate\Foundation\Testing\DatabaseMigrations; class ExampleTest ...

The steps of overload resolution are: Find candidate functions via name lookup. Unqualified calls will perform both regular unqualified lookup as well as argument-dependent lookup (if applicable). Filter the set of candidate functions to a set of viable functions. A viable function for whi...

really_neat.info name = Really Neat Module description = Provides a really neat page for your site core = 7.x really_neat.module <?php /** * @file * Hook implementation and shared functions for the Really Neat Module. */ /** * Implements hook_menu(). */ function really_nea...

Recursion can be defined as: A method that calls itself until a specific condition is met. An excellent and simple example of recursion is a method that will get the factorial of a given number: public int Factorial(int number) { return number == 0 ? 1 : n * Factorial(number - 1); } ...

In the timeline of any DisplayObject that is attached as a descendant of the display tree, you can utilise the root property. This property points to the main timeline in the case of no custom document class, or the document class if you do define one. Because root is typed DisplayObject, the compi...

Enums are iterable: class Color(Enum): red = 1 green = 2 blue = 3 [c for c in Color] # [<Color.red: 1>, <Color.green: 2>, <Color.blue: 3>]

You can use all() to determine if all the values in an iterable evaluate to True nums = [1, 1, 0, 1] all(nums) # False chars = ['a', 'b', 'c', 'd'] all(chars) # True Likewise, any() determines if one or more values in an iterable evaluate to True nums = [1, 1, 0, 1] any(nums) # True val...

private static final int REQUEST_ENABLE_BT = 1; // Unique request code BluetoothAdapter mBluetoothAdapter; // ... if (!mBluetoothAdapter.isEnabled()) { Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); startActivityForResult(enableBtIntent, REQUEST_ENABLE_B...

private static final int REQUEST_DISCOVERABLE_BT = 2; // Unique request code private static final int DISCOVERABLE_DURATION = 120; // Discoverable duration time in seconds // 0 means always discoverable ...

Declare a BluetoothAdapter first. BluetoothAdapter mBluetoothAdapter; Now create a BroadcastReceiver for ACTION_FOUND private final BroadcastReceiver mReceiver = new BroadcastReceiver() { public void onReceive(Context context, Intent intent) { String action = intent.getAction(); //...

A list of recognised color keyword names can be found in the W3C Recommendation for SVG. <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <circle r="30" cx="100" cy="100" fill="red" stroke=&qu...

<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <circle r="30" cx="100" cy="100" fill="#ff0000" stroke="#00ff00" /> <rect x="200" y="200" width="50&...

Count returns the number of elements in an IEnumerable<T>. Count also exposes an optional predicate parameter that allows you to filter the elements you want to count. int[] array = { 1, 2, 3, 4, 2, 5, 3, 1, 2 }; int n = array.Count(); // returns the number of elements in the array int x ...

To search for a string inside a string, there are several functions: indexOf( searchString ) and lastIndexOf( searchString ) indexOf() will return the index of the first occurrence of searchString in the string. If searchString is not found, then -1 is returned. var string = "Hello, World!&q...

Sometimes it is useful to have multiple validations use one condition. It can be easily achieved using with_options. class User < ApplicationRecord with_options if: :is_admin? do |admin| admin.validates :password, length: { minimum: 10 } admin.validates :email, presence: true end...

This type of association allows an ActiveRecord model to belong to more than one kind of model record. Common example: class Human < ActiveRecord::Base has_one :address, :as => :addressable end class Company < ActiveRecord::Base has_one :address, :as => :addressable end cl...

The idea here is to move the computationally intensive jobs to C (using special macros), independent of Python, and have the C code release the GIL while it's working. #include "Python.h" ... PyObject *pyfunc(PyObject *self, PyObject *args) { ... Py_BEGIN_ALLOW_THREADS //...

Support vector machines is a family of algorithms attempting to pass a (possibly high-dimension) hyperplane between two labelled sets of points, such that the distance of the points from the plane is optimal in some sense. SVMs can be used for classification or regression (corresponding to sklearn.s...

A random forest is a meta estimator that fits a number of decision tree classifiers on various sub-samples of the dataset and use averaging to improve the predictive accuracy and control over-fitting. A simple usage example: Import: from sklearn.ensemble import RandomForestClassifier Define tr...