Month: September 2017

Block is an interesting ruby languange feature. Block is statements enclosed together using do end or curly braces {}. We can find block in action at code that iterating  an array variable.

Lets try block on irb (interactive ruby)  !!!

Sample above creating variable x which is an array of string. Next command iterating the array using each method and a block passed to it. The block have a parameter named n and n will contain each array element passed to it by each method. Code inside block print output to screen.

Below is an example of block using curly braces.

That is simple examples of block in ruby language. It is an unique and usefull feature.

Bye for now !

Open Classes

A class in ruby can be modified by adding method or variable at any point in the code.

Sample code as follow :

class ClassA
  def method1
   puts '1'
  end
end

var1 = ClassA.new
var1.method1

class ClassA
 def method2
 puts '2'
 end
end

var1.method2
var1.method1

 

Hashes

A hash is a collection of key and value pairs. Use curly braces {} to define a hash. Use brackets [] to get a value of a key from a hash.

Define a hash like below

nations = { ‘ID’ => ‘Indonesia’ , ‘MY’ => ‘Malaysia’, ‘SG’ => ‘Singapore’ }

To add a key value pair to hash

nations[‘BN’] = ‘Brunei Darussalam’

To output value of a key in hash

puts nations[‘ID’]

To output a hash entirely

puts nations

Bye for now !