Tutorial by Examples: ce

The instance_eval method is available on all objects. It evaluates code in the context of the receiver: object = Object.new object.instance_eval do @variable = :value end object.instance_variable_get :@variable # => :value instance_eval sets self to object for the duration of the c...

Many languages feature a with statement that allows programmers to omit the receiver of method calls. with can be easily emulated in Ruby using instance_eval: def with(object, &block) object.instance_eval &block end The with method can be used to seamlessly execute methods on object...

To better understand the semantics of conses and lists, a graphical representation of this kind of structures is often used. A cons cell is usually represented with two boxes in contact, that contain either two arrows that point to the car and cdr values, or directly the values. For instance, the re...

Its possible to change *.vmoptions and idea.properties files without editing them in the PhpStorm installation folder. Follow the steps below: Step 1: Run Help - Edit Custom VM Options... Step 2: Confirm the creation of the configuration file, if prompted Step 3: Add following lines if yo...

If Sitecore is setup in a CM-CD enviornment there could be a need to fire events on CD server when CM events are fired. The example could be firing publish:end:remote on CD when content editors done publish on CM. In order to make sure that events are firing the following steps are required to be ...

Python follows PEMDAS rule. PEMDAS stands for Parentheses, Exponents, Multiplication and Division, and Addition and Subtraction. Example: >>> a, b, c, d = 2, 3, 5, 7 >>> a ** (b + c) # parentheses 256 >>> a * b ** c # exponent: same as `a * (b ** c)` 7776 >>...

The instance_eval method is available on all objects. It evaluates code in the context of the receiver: object = Object.new object.instance_eval do @variable = :value end object.instance_variable_get :@variable # => :value instance_eval sets self to object for the duration of the co...

When the only thing returned from a function is a recursive call, it is refered to as tail recursion. Here's an example countdown written using tail recursion: def countdown(n): if n == 0: print "Blastoff!" else: print n countdown(n-1) Any computat...

Suppose we have an array of integers and we want to figure out the maximum value without holding the whole array in memory all at once. This approach can be adapted to handle a variety of other situations in which data needs to be processed while being deserialized instead of after. extern crate se...

Placeholders can be used in strings to automatically substitute the values in the final string. container = "cup" liquid = "coffee" string = "Filling the #{container} with #{liquid}..." The above String - when printed - will say: Filling the cup with coffee... Yo...

Do not allocate new objects in onDraw @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); Paint paint = new Paint(); //Do not allocate here } Instead of drawing drawables in canvas... drawable.setBounds(boundsRect); drawable.draw(canvas); Use a B...

One of the useful unit when creating a responsive application. Its size depends on its parent container. Equation: ( Parent Container`s width ) * ( Percentage(%) ) = Output For Example: Parent has 100px width while the Child has 50%. On the output, the Child's width will be half(50%) of t...

HTML: <div class="wrapper"> <div class="outer"> <div class="inner"> centered </div> </div> </div> CSS: .wrapper { height: 600px; text-align: center; } .outer { display: table; ...

HTML: <div class="wrapper"> <div class="centered"> centered </div> </div> CSS: .wrapper { position: relative; height: 600px; } .centered { position: absolute; z-index: 999; transform: translate(-50%, -50%); top:...

Typed holes can make it easier to define functions, through an interactive process. Say you want to define a class instance Foo Bar (for your custom Bar type, in order to use it with some polymorphic library function that requires a Foo instance). You would now traditionally look up the documentati...

git clean -f Will remove all untracked files.

:q! ZQ

:wq!

To get started with unit testing, which will be done in the tests file and will be testing the View Controller and Storyboard, we should introduce these two files to the test file. Defining the View Controller Swift var viewController : ViewController! Introducing the Storyboard and initializi...

class Example def example_method :example end def subexample_method :example end def not_missed_method :example end def method_missing name return :example if name == :missing_example_method return :example if name == :missing_subexample_method ...