Tutorial by Examples: l

To initialize a static final fields that require using more than a single expression, a static initializer can be used to assign the value. The following example initializes a unmodifiable set of Strings: public class MyClass { public static final Set<String> WORDS; static {...

Orthogonal to the JRE versus JDK dichotomy, there are two types of Java release that are widely available: The Oracle Hotspot releases are the ones that you download from the Oracle download sites. The OpenJDK releases are the ones that are built (typically by third-party providers) from the Ope...

A JDK installation and a text editor are the bare minimum for Java development. (It is nice to have a text editor that can do Java syntax highlighting, but you can do without.) However for serious development work it is recommended that you also use the following: A Java IDE such as Eclipse, In...

It is possible to create a set of variables that can act similar to an array (although they are not an actual array object) by using spaces in the SET statement: @echo off SET var=A "foo bar" 123 for %%a in (%var%) do ( echo %%a ) echo Get the variable directly: %var% Result: ...

Adjustments can be done for specific platforms from C# code, for example for changing padding for all the targeted platforms. if (Device.OS == TargetPlatform.iOS) { panel.Padding = new Thickness (10); } else { panel.Padding = new Thickness (20); } An helper method is also availab...

When working with XAML, using a centralized Style allows you to update a set of styled views from one place. All the idiom and platform adjustements can also be integrated to your styles. <Style TargetType="StackLayout"> <Setter Property="Padding"> <Setter...

Creating variables in VBScript can be done by using the Dim, Public, or Private statement. It is best practice to put at the top of the script "Option Explicit" which forces you to explicitly define a variable. You can declare one variable like this: Option Explicit Dim firstName O...

Here are some ways to set variables: You can set a variable to a specific, string, number, date using SET EX: SET @var_string = 'my_var'; SET @var_num = '2' SET @var_date = '2015-07-20'; you can set a variable to be the result of a select statement using := EX: Select @var := '123'; (...

To move to split on left, use <C-w><C-h> To move to split below, use <C-w><C-j> To move to split on right, use <C-w><C-k> To move to split above, use <C-w><C-l>

It's a better experience to open split below and on right set it using set splitbelow set splitright

Assume you want to delegate to a class but you do not want to provide the delegated-to class in the constructor parameter. Instead, you want to construct it privately, making the constructor caller unaware of it. At first this might seem impossible because class delegation allows to delegate only to...

Person = Struct.new :name do def greet(someone) "Hello #{someone}! I am #{name}!" end end Person.new('Alice').greet 'Bob' # => "Hello Bob! I am Alice!"

Attributes can be accessed strings and symbols as keys. Numerical indexes also work. Person = Struct.new :name alice = Person.new 'Alice' alice['name'] # => "Alice" alice[:name] # => "Alice" alice[0] # => "Alice"

List comprehensions can introduce local bindings for variables to hold some interim values: [(x,y) | x <- [1..4], let y=x*x+1, even y] -- [(1,2),(3,10)] Same effect can be achieved with a trick, [(x,y) | x <- [1..4], y <- [x*x+1], even y] -- [(1,2),(3,10)] The let in list compr...

filter returns a list of each item in the given list for which the given predicate returns a non-#f value. ;; Get only even numbers in a list > (filter even? '(1 2 3 4)) '(2 4) ;; Get all square numbers from 1 to 100 > (filter (lambda (n) (integer? (sqrt n))) (range 1 100)) '(1 4 9 16 ...

// circle objects: { x:, y:, radius: } // return true if the 2 circles are colliding // c1 and c2 are circles as defined above function CirclesColliding(c1,c2){ var dx=c2.x-c1.x; var dy=c2.y-c1.y; var rSum=c1.radius+c2.radius; return(dx*dx+dy*dy<=rSum*rSum); }

// rectangle objects { x:, y:, width:, height: } // return true if the 2 rectangles are colliding // r1 and r2 are rectangles as defined above function RectsColliding(r1,r2){ return !( r1.x>r2.x+r2.width || r1.x+r1.width<r2.x || r1.y>r2.y+r2.height || ...

// rectangle object: { x:, y:, width:, height: } // circle object: { x:, y:, radius: } // return true if the rectangle and circle are colliding function RectCircleColliding(rect,circle){ var dx=Math.abs(circle.x-(rect.x+rect.width/2)); var dy=Math.abs(circle.y-(rect.y+rect.height/2));...

The function in this example returns true if two line segments are intersecting and false if not. The example is designed for performance and uses closure to hold working variables // point object: {x:, y:} // p0 & p1 form one segment, p2 & p3 form the second segment // Retur...

// [x0,y0] to [x1,y1] define a line segment // [cx,cy] is circle centerpoint, cr is circle radius function isCircleSegmentColliding(x0,y0,x1,y1,cx,cy,cr){ // calc delta distance: source point to line start var dx=cx-x0; var dy=cy-y0; // calc delta distance: line start to e...