Enumerable is the most popular module in Ruby. Its purpose is to provide you with iterable methods like map, select, reduce, etc. Classes that use Enumerable include Array, Hash, Range.
To use it, you have to include Enumerable and implement each.
class NaturalNumbers
include Enumerable
de...
The core concepts of RxJava are its Observables and Subscribers. An Observable emits objects, while a Subscriber consumes them.
Observable
Observable is a class that implements the reactive design pattern. These Observables provide methods that allow consumers to subscribe to event changes. The ev...
Comparable is one of the most popular modules in Ruby. Its purpose is to provide with convenience comparison methods.
To use it, you have to include Comparable and define the space-ship operator (<=>):
class Rectangle
include Comparable
def initialize(a, b)
@a = a
@b = b
...
DELETE FROM `table_name` WHERE `field_one` = 'value_one'
This will delete all rows from the table where the contents of the field_one for that row match 'value_one'
The WHERE clause works in the same way as a select, so things like >, <, <> or LIKE can be used.
Notice: It is necessa...
DELETE FROM table_name ;
This will delete everything, all rows from the table. It is the most basic example of the syntax. It also shows that DELETE statements should really be used with extra care as they may empty a table, if the WHERE clause is omitted.
DELETE FROM `table_name` WHERE `field_one` = 'value_one' LIMIT 1
This works in the same way as the 'Delete with Where clause' example, but it will stop the deletion once the limited number of rows have been removed.
If you are limiting rows for deletion like this, be aware that it will delete th...
CommandDescription<C-w>Delete word before cursor<C-t>Indent current line with by one shiftwidth<C-d>Unindent current line with by one shiftwidth<C-f>reindent the line, (move cursor to auto indent position)<C-a>Insert previously inserted text<C-e>Insert the charact...
Privileges
The CREATE VIEW statement requires the CREATE VIEW privilege for the view, and some privilege for each column selected by the SELECT statement. For columns used elsewhere in the SELECT statement, you must have the SELECT privilege. If the OR REPLACE clause is present, you must also have ...
Statement-level parallel hints are the easiest:
SELECT /*+ PARALLEL(8) */ first_name, last_name FROM employee emp;
Object-level parallel hints give more control but are more prone to errors; developers often forget to use the alias instead of the object name, or they forget to include some objec...
4.0.3
Using a CustomTabsIntent, it is now possible to configure Chrome custom tabs in order to customize key UI components in the browser that is opened from your app.
This is a good alternative to using a WebView for some cases. It allows loading of a web page with an Intent, with the added abil...
In C#, there are two different kinds of equality: reference equality and value equality. Value equality is the commonly understood meaning of equality: it means that two objects contain the same values. For example, two integers with the value of 2 have value equality. Reference equality means that ...
There are few approaches available there:
You can subscribe for keyboard appearance events notifications and change offset manually:
//Swift 2.0+
override func viewDidLoad() {
super.viewDidLoad()
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(YourVCClas...
Controller class names are pluralized. The reason is the controller controls multiple instances of object instance.
For Example: OrdersController would be the controller for an orders table. Rails will then look for the class definition in a file called orders_controller.rb in the /app/controllers ...
Private inheritance is useful when it is required to restrict the public interface of the class:
class A {
public:
int move();
int turn();
};
class B : private A {
public:
using A::turn;
};
B b;
b.move(); // compile error
b.turn(); // OK
This approach efficiently pr...
To show some content in a new window, a Stage needs to be created. After creation and initialisation show or showAndWait needs to be called on the Stage object:
// create sample content
Rectangle rect = new Rectangle(100, 100, 200, 300);
Pane root = new Pane(rect);
root.setPrefSize(500, 500);
...
If you have an existing class that you'd like to use, perform Step 2 and then skip to Step 5. (For some cases, I had to add an explicit #import <Foundation/Foundation.h to an older ObjC File)
Step 1: Add Objective-C Implementation -- .m
Add a .m file to your class, and name it CustomObje...
