Tutorial by Examples: i

To delete persisted objects use delete(): session.delete(obj) Actual deletion from the database will happen on next flush.

There are many ways find the location of a value in an array. The following example snippets all assume that the array is one of the following: String[] strings = new String[] { "A", "B", "C" }; int[] ints = new int[] { 1, 2, 3, 4 }; In addition, each one sets...

Using ActiveCell or ActiveSheet can be source of mistakes if (for any reason) the code is executed in the wrong place. ActiveCell.Value = "Hello" 'will place "Hello" in the cell that is currently selected Cells(1, 1).Value = "Hello" 'will always place "Hello&...

Implementing the IEnumerable interface allows classes to be enumerated in the same way as BCL collections. This requires extending the Enumerator class which tracks the state of the enumeration. Other than iterating over a standard collection, examples include: Using ranges of numbers based on a...

Uploading Files Uploading files in Yii is usually done with the help of [[yii\web\UploadedFile]] which encapsulates each uploaded file as an UploadedFile object. Combined with [[yii\widgets\ActiveForm]] and models, you can easily implement a secure file uploading mechanism. Creating Models Lik...

So you've uploaded your files to a folder say /backend/web/uploads/ and you want these uploads to be visible on the frontend too. The easiest option is to create a symlink in the frontend that links to the backend: ln -s /path/to/backend/web/uploads/ /path/to/frontend/web/uploads In your views y...

The <algorithm> header provides a number of useful functions for working with sorted vectors. An important prerequisite for working with sorted vectors is that the stored values are comparable with <. An unsorted vector can be sorted by using the function std::sort(): std::vector<int&...

Trying to use several traits into one class could result in issues involving conflicting methods. You need to resolve such conflicts manually. For example, let's create this hierarchy: trait MeowTrait { public function say() { print "Meow \n"; } } trait WoofTrait {...

Note: it's strongly advised to use Composer. The instruction below is basically what Composer does for you. Download archive extension file of needed version from Github Open composer.json Find PSR-4 autoload section and remember it for e.g. kmit/select2 Extract files to corresponding fold...

() is a Monoid. Since there is only one value of type (), there's only one thing mempty and mappend could do: instance Monoid () where mempty = () () `mappend` () = ()

SharedPreferences allows you to store primitive data types only (boolean, float, long, int, String, and string set). You cannot store more complex objects in SharedPreferences, and as such is really meant to be a place to store user settings or similar, it's not meant to be a database to keep user d...

public class Customer { public void SendEmail() { // Sending email code here } } List<Customer> customers = new List<Customer>(); customers.Add(new Customer()); customers.Add(new Customer()); customers.ForEach(c => c.SendEmail());

ForEach() is defined on the List<T> class, but not on IQueryable<T> or IEnumerable<T>. You have two choices in those cases: ToList first The enumeration (or query) will be evaluated, copying the results into a new list or calling the database. The method is then called on each it...

Install Codeception: composer global status composer global require "codeception/codeception=~2.0.0" "codeception/specify=*" "codeception/verify=*" Install Faker: cd /var/www/yii // Path to your application composer require --de...

If you need to count distinct characters then, for the reasons explained in Remarks section, you can't simply use Length property because it's the length of the array of System.Char which are not characters but code-units (not Unicode code-points nor graphemes). If, for example, you simply write tex...

We cannot break a string into arbitrary points (because a System.Char may not be valid alone because it's a combining character or part of a surrogate) then code must take that into account (note that with length I mean the number of graphemes not the number of code-units): public static IEnumerabl...

.NET strings contain System.Char (UTF-16 code-units). If you want to save (or manage) text with another encoding you have to work with an array of System.Byte. Conversions are performed by classes derived from System.Text.Encoder and System.Text.Decoder which, together, can convert to/from another ...

Sometimes a element needs to be created outside of the usual object structure in the fxml. This is where Define Blocks come into play: Contents inside a <fx:define> element are not added to the object created for the parent element. Every child element of the <fx:define> needs a fx:id...

If there are no specific needs, choose x86_64 system images with Google APIs to create the emulator. It works way faster than armeabi-v7a on intel x86 x64 based computers. There are some SDK libraries compiled and designed with ARM architecture. If you try to install them on Intel based emulators...

Table Item The following class contains 2 properties a name (String) and the size (double). Both properties are wrapped in JavaFX properties to allow the TableView to observe changes. import javafx.beans.property.DoubleProperty; import javafx.beans.property.SimpleDoubleProperty; import javafx.be...