Tutorial by Examples: v

The common idiom for loading shared library files in Java is the following : public class ClassWithNativeMethods { static { System.loadLibrary("Example"); } public native void someNativeMethod(String arg); ... Calls to System.loadLibrary are almost always...

Quite often you have a file which was edited within DOS or Windows and you are viewing it under UNIX. This can look like the following when you view the file with vi. First line of file^M Next Line^M And another^M If you wish to remove the ^M, it can be that you delete each ^M by hand. Alter...

All actions performed in a timer are handled in the "Tick" event. public partial class Form1 : Form { Timer myTimer = new Timer(); public Form1() { InitializeComponent(); myTimer.Tick += myTimer_Tick; //assign the event handler named "myT...

class MyDataObject extends DataObject { ... private static $has_many = array( 'OtherDataObjects' => 'OtherDataObject' ); function getCMSFields() { $fields = parent::getCMSFields(); if ($gridField = $fields->dataFieldByName('OtherDataObject...

class MyAdmin extends ModelAdmin { ... function getEditForm($id = null, $fields = null) { $form = parent::getEditForm($id, $fields); if ($this->modelClass == 'MyDataObjectName') { $form->Fields() ->fieldByName($this->sanitis...

Objects that respond to to_proc can be converted to procs with the & operator (which will also allow them to be passed as blocks). The class Symbol defines #to_proc so it tries to call the corresponding method on the object it receives as parameter. p [ 'rabbit', 'grass' ].map( &:upcase ) ...

Given the following DataFrame: In [11]: df = pd.DataFrame(np.random.randn(6, 3), columns=['A', 'B', 'C']) In [12]: df.set_index(['A', 'B'], inplace=True) In [13]: df Out[13]: C A B 0.902764 -0.259656 -1.864541 -0.695893 0.308893 0...

Given the following DataFrame: In [11]: df = pd.DataFrame({'a':[1,1,1,2,2,3],'b':[4,4,5,5,6,7,],'c':[10,11,12,13,14,15]}) In [12]: df.set_index(['a','b'], inplace=True) In [13]: df Out[13]: c a b 1 4 10 4 11 5 12 2 5 13 6 14 3 7 15 You can iterate by any lev...

The Foundation framework provides the Operation type, which represents a high-level object that encapsulates a portion of work that may be executed on a queue. Not only does the queue coordinate the performance of those operations, but you can also establish dependencies between operations, create c...

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Java configuration is typically done by applying the @Configuration annotation to a class to suggest that a class contains bean definitions. The bean definitions are specified by applying the @Bean annotation to a method that returns an object. @Configuration // This annotation tells the Applicati...

The remainder operator in Julia is the % operator. This operator behaves similarly to the % in languages such as C and C++. a % b is the signed remainder left over after dividing a by b. This operator is very useful for implementing certain algorithms, such as the following implementation of the Si...

Some LINQ methods return a query object. This object does not hold the results of the query; instead, it has all the information needed to generate those results: var list = new List<int>() {1, 2, 3, 4, 5}; var query = list.Select(x => { Console.Write($"{x} "); return ...

Modify your Gemfile to include the Devise gem: gem 'devise' Then update your gems with: $ bundle install Run the installers in your project: $ rails generate devise:install Then create your Devise model (e.g. User) with: $ rails generate devise User you'll need to set up the default ...

class CreateAuthenticationProviders < ActiveRecord::Migration def change create_table "authentication_providers", :force => true do |t| t.string "name" t.datetime "created_at", :null => false ...

has_many :users has_many :user_authentications

For Facebook config.omniauth :facebook, facebook_app_id, facebook_secret_key, :display => "popup", :scope => 'email,publish_actions', info_fields: 'email,name' For Twitter config.omniauth :twitter, twitter_app_id, twitter_secret_key, :display => "popup", :scope =&gt...

The System.Web.SessionState.HttpSessionState object provides a way to persist values between HTTP requests. In the example below, a user's preference for warnings is being saved in the session. Later on, while serving another request to the user, the application can read this preference from session...

When one wishes to convert a list to a vector or data.frame object empty elements are typically dropped. This can be problematic which a list is created of a desired length are created with some empty values (e.g. a list with n elements is created to be added to an m x n matrix, data.frame, or data...

returnType (^blockName)(parameterType1, parameterType2, ...) = ^returnType(argument1, argument2, ...) {...}; float (^square)(float) = ^(float x) {return x*x;}; square(5); // resolves to 25 square(-7); // resolves to 49 Here's an example with no return and no parameters: NSMutableDicti...