Ruby notes

Learn Ruby language via style guide is interesting
https://github.com/bbatsov/ruby-style-guide

Goodies:
http://docs.ruby-lang.org/en/2.2.0/Enumerable.html
http://docs.ruby-lang.org/en/2.2.0/syntax/modules_and_classes_rdoc.html

My discoveries:

print : echo bare text

p: print object as it as, with new line

puts: echo text with new line

alias create alias for existing method, var

ensure always executed at block termination

block comment

=begin 

=end

undef remove function definition

convention:

Eg: eql?

method with a question mark return a bool value

Eg: delete! (bang symbol)

method with exclamation ! indicates that it's destructive: change object than a copy

Eg: name=

method ends with = is a setter

block can be wrapped by "do .. end" or { }

run by "yield"

Check for existence via if block_given?

:symbol 

storage optimized string

Global names is from Kernel module

replace string once:

string['search']= 'replace'

replace all

string.gsub 'search', 'replace'

regex

string[/regex/]

regex replace uses the same syntax

string.split(/, /) you might guess

Object methods:

obj.to_s

obj.class

string.to_sym -> :symbol

num_string.to_i -> integer

range.to_a -> array

%w[ string1, ... ]

%i [ symbol1, ...]

[num1, ... ]

array << x # Add x to array (immuttable)

set operator: intersect &, diffeence -, union | 

array.join sep

array.shift

Hash.new(default_value)

hash.key?

hash.value?

hash.keys

hash.values