Method In Ruby

To say mooooo:

>> def sayMoo

>> puts 'Mooooooooooo...'

>> end

To call it, just type:
>> sayMoo

Method with parameter:

>> def sayMoo num

>> puts 'Mooooooooo...'*num

>> end

Call it by
>> sayMoo 5        # print 5 times

Method In Ruby

Classes In Ruby

You creating class by:

>> class Satu

>>     def hello

>>         puts 'hello for you'

>>     end

>> end

Then you instantiate an object, write:

>> data = Satu.new

>> data.hello

Other example for creating an array:
>> class Satu
>>     def initialize name    # constructor
>>         @name = name    # @ is the class data
>>     end
>>     def setName name
>>         @name = name
>>     end
>>     def getName
>>         @name
>>     end
>> end

To instantiate an object, use:
>> data = Satu.new 'lady gaga'
>> puts data.getName    # print out 'lady gaga'
>> data.setName 'luna maya'  # 'luna maya' for getName

Classes In Ruby

Hash In Ruby

Hash in Ruby is like map in Java:

You can instantiate it like below:

data = {}

or

data = Hash.new

Then you insert an element toward it like below:

data['lady'] = 'gaga'

data['luna'] = 'maya'

data['aura'] = 'kasih'

To iterate to all of the hash, you need to type:

data.each do |key, value|

puts key +': '+value

end

Hash In Ruby

Array In Ruby

To define an array, use:

>> data = []

>> data[0] = 'lady gaga'

>> data[1] = 24

>> data[2] = 'new york'

or
>> data = ['lady gaga', 24, 'new york']

or

>> datas = [
>>       ['lady gaga','new york'],
>>       ['aura kasih','jakarta'],
>>       ['bill clinton','virginia']
>>     ]

To access an element, use the index:

>> puts data[0]     # lady gaga

>> puts datas[1][0]   # aura kasih

To iterate through all elements in the array, use:

>> data.each do |value|

>> puts value

>> end

To repeat the same thing over some times, use:

>> 3.times do

>> puts 'Holla World'

>> end
    
Other methods:

>> data.push 'barack obama'

>> data.pop            # remove and return the last element

>> data.length

>> data.last               # retrieve the last element

Array In Ruby

While Loop In Ruby

while looping

>> comment = ''

>> while comment!='bye'

>> puts comment

>> comment = gets.chomp

>> end


Code to iterate:

>> i = 0;

>> while i<=10

>> puts i

>> i = i+1   # cannot use i++

>> end

While Loop In Ruby

Flow Control In Ruby

Simple expression in comparison:

>> puts 2<1         // result false

>> puts 2!=8       // result true

Use if:

>> if (9>8)

>> puts '9 is greater than 8'

>> puts 'Hope you happy' 

>> else

>> puts '9 is not greater than 8'

>> end

Flow Control In Ruby

Ruby - Basic

To prompt output in colsole of Ruby, use:

>>> puts 'hello world!'    // single or double quotes is same

>> hello world

String aritmathics:

>>> puts 'one '+'day'

>> one day

>>> puts 'lol '*5

>> lol lol lol lol lol

To convert from number to string, use:

>>> id = 45

>>> puts id.to_s + ' indonesia raya'

>> 45 indonesia raya

To convert from string to number, use:

>>> code = '45'

>>> puts code.to_i + 5

>> 50

To convert from string to float, use:

>>> code = '45.3'

>>> puts code.to_f + 0.7

>> 46.0

Get input from keyboard:

>>> puts gets

>> holla for you all

>>> holla for you all

Binding keyboard input to variable:

>>> name = gets

>> sergey brin

>>> puts 'Your name is: '+ name +' and it's okey'

>> Your name is: sergey brin

>>  and it's okey

Removing CR-LF from gets

>>> name = gets.chomp

>> sergey brin

>>> puts 'Your name is: '+name+' and it's okey'

>> Your name is: sergey brin and it's okey

# sign is used for inline comment 

Ruby - Basic