Tutorial by Examples: ce

Facebook SDK 4.0 onwards, this is how we logout: com.facebook.login.LoginManager.getInstance().logOut(); For versions before 4.0, the logging out is gone by explicitly clearing the access token: Session session = Session.getActiveSession(); session.closeAndClearTokenInformation();

If you want your application to support a plug-in system, for example to load plug-ins from assemblies located in plugins folder: interface IPlugin { string PluginDescription { get; } void DoWork(); } This class would be located in a separate dll class HelloPlugin : IPlugin { ...

from __future__ import print_function import multiprocessing def countdown(count): while count > 0: print("Count value", count) count -= 1 return if __name__ == "__main__": p1 = multiprocessing.Process(target=countdown, args=(10,)) ...

The first thing you need to do is create a connection to the database using the connect method. After that, you will need a cursor that will operate with that connection. Use the execute method of the cursor to interact with the database, and every once in a while, commit the changes using the comm...

[ContractClass(typeof(ValidationContract))] interface IValidation { string CustomerID{get;set;} string Password{get;set;} } [ContractClassFor(typeof(IValidation))] sealed class ValidationContract:IValidation { string IValidation.CustomerID { [Pure] get ...

Swift class PickerViewExampleViewController : UIViewController, UIPickerViewDelegate, UIPickerViewDataSource { @IBOutlet weak var btnFolder: UIButton! let pickerView = UIPickerView() let pickerViewRows = ["First row,", "Secound row,","Third row,","F...

This example is written with F# in mind but the ideas are applicable in all environments The first rule when optimizing for performance is to not to rely assumption; always Measure and Verify your assumptions. As we are not writing machine code directly it is hard to predict how the compiler an...

This linker error happens, if the linker can't find a used symbol. Most of the time, this happens if a used library is not linked against. qmake: LIBS += nameOfLib cmake: TARGET_LINK_LIBRARIES(target nameOfLib) g++ call: g++ -o main main.cpp -Llibrary/dir -lnameOfLib One might also for...

eof returns true only after reading the end of file. It does NOT indicate that the next read will be the end of stream. while (!f.eof()) { // Everything is OK f >> buffer; // What if *only* now the eof / fail bit is set? /* Use `buffer` */ } You could correctly write: ...

Extended asm support in gcc has the following syntax: asm [volatile] ( AssemblerTemplate : OutputOperands [ : InputOperands [ : Clobbers ] ]) asm [volatile] goto ( AssemblerTemplate : : Inp...

Jupyter Notebooks are an interactive, browser-based development environment. They were originally developed to run computation python and as such play very well with numpy. To try numpy in a Jupyter notebook without fully installing either on one's local system Rackspace provides free temporary note...

SQL has various join types to specify whether (non-)matching rows are included in the result: INNER JOIN, LEFT OUTER JOIN, RIGHT OUTER JOIN, and FULL OUTER JOIN (the INNER and OUTER keywords are optional). The figure below underlines the differences between these types of joins: the blue area repres...

Pre-processing in caret is done through the preProcess() function. Given a matrix or data frame type object x, preProcess() applies transformations on the training data which can then be applied to testing data. The heart of the preProcess() function is the method argument. Method operations are ap...

Inherits Specifies the base (or parent) class Public Class Person End Class Public Class Customer Inherits Person End Class 'One line notation Public Class Student : Inherits Person End Class Possible objects: Dim p As New Person Dim c As New Customer Dim s As New Student ...

Overridable Allows a property or method in a class to be overridden in a derived class. Public Class Person Public Overridable Sub DoSomething() Console.WriteLine("Person") End Sub End Class Overrides Overrides an Overridable property or method defined in the base...

Public Interface IPerson Sub DoSomething() End Interface Public Class Customer Implements IPerson Public Sub DoSomething() Implements IPerson.DoSomething Console.WriteLine("Customer") End Sub End Class

In C, character constants and string literals are different things. A character surrounded by single quotes like 'a' is a character constant. A character constant is an integer whose value is the character code that stands for the character. How to interpret character constants with multiple charac...

Returns a string (varchar or nvarchar) where all occurrences of a specified sub string is replaced with another sub string. Parameters: string expression. This is the string that would be searched. It can be a character or binary data type. pattern. This is the sub string that would be replaced...

There are two ways to get singleton class of an object singleton_class method. Reopening singleton class of an object and returning self. object.singleton_class singleton_class = class << object self end

Singleton classes share their instance/class variables with their object. class Example @@foo = :example end def Example.foo class_variable_get :@@foo end Example.foo #=> :example class Example def initialize @foo = 1 end def foo @foo end end e = Ex...