Tutorial by Examples: v

The Observer pattern is used for event handling and delegation. A subject maintains a collection of observers. The subject then notifies these observers whenever an event occurs. If you've ever used addEventListener then you've utilized the Observer pattern. function Subject() { this.observers...

git diff HEAD^ HEAD This will show the changes between the previous commit and the current commit.

These examples assume that you already know what Java 7's NIO is in general, and you are used to writing code using java.io.File. Use these examples as a means to quickly find more NIO-centric documentation for migrating. There is much more to Java 7's NIO such as memory-mapped files or opening a Z...

mconcat :: [a] -> a is another method of the Monoid typeclass: ghci> mconcat [Sum 1, Sum 2, Sum 3] Sum {getSum = 6} ghci> mconcat ["concat", "enate"] "concatenate" Its default definition is mconcat = foldr mappend mempty.

Suppose you have this type: data Person = Person { name :: String, age:: Int } deriving (Show, Eq) and two values: alex = Person { name = "Alex", age = 21 } jenny = Person { name = "Jenny", age = 36 } a new value of type Person can be created by copying from alex, specif...

import pandas as pd # Save dataframe to pickled pandas object df.to_pickle(file_name) # where to save it usually as a .plk # Load dataframe from pickled pandas object df= pd.read_pickle(file_name)

Using scenario you can perform validation on different situation Define scenario in model class class User extends \yii\db\ActiveRecord { public static function tableName() { return 'user_master'; } // define validation in rule() function public ...

Vector based graphics are represented by a plethora of data that must be computed by the CPU (vector points, arcs, colors, etc). Anything other than simple shapes with minimal points and straight lines will consume vast amounts of CPU resource. There is a "Cache as Bitmap" flag that can b...

Using the Vector.<T> type and the for each loop is more performant than a conventional array and for loop: Good: var list:Vector.<Sprite> = new <Sprite>[]; for each(var sprite:Sprite in list) { sprite.x += 1; } Bad: var list:Array = []; for (var i:int = 0; i < ...

If you do not require an array to be in any particular order, a little trick with pop() will afford you enormous performance gains compared to splice(). When you splice() an array, the index of subsequent elements in that array needs to be reduced by 1. This process can consume a large chunk of tim...

If you have a value that you use often, you can store it in a variable. You could use this to define color schemes, for example. You would only have to define your scheme once and then you could use it throughout your stylesheets. To define a variable, you must prefix its name with the $ symbol. (L...

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&...

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&...

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...

.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 ...

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...

PropertyValueFactory can be used as cellValueFactory in a TableColumn. It uses reflection to access methods that match a certain pattern to retrieve the data from a TableView item: Example TableColumn<Person, String> nameColumn = ... PropertyValueFactory<Person, String> valueFactory =...

The below examples use the new form API introduced in RC3. pw-change.template.html <form class="container" [formGroup]="pwChangeForm"> <label for="current">Current Password</label> <input id="current" formControlName="curr...

Characteristics of properties : Properties that can be retrieved from an object could have the following characteristics, Enumerable Non - Enumerable own While creating the properties using Object.defineProperty(ies), we could set its characteristics except "own". Properties which...

The .vimrc file (pronounced Vim-wreck) is a Vim configuration file. It holds commands that will be executed by Vim every time it starts. By default the file is empty or non-existent; you can use it to customize your Vim environment. To find out where Vim expects the vimrc file to be stored, open V...