ruby-start-flow.md

ruby-training-plan

Plan for a training on Ruby language to new interns

Day's Schedule:

• 2-3 hours of interactive training
• Rest of the day:
  • few questions related to what was taught
  • a coding assignment
  • the interns will interact with their mentors throughout the day

For each topic:

• subjective questions
• coding assignments

Topics:

• installation of ruby, git
• git basics
• ruby intro:
  • why ruby?
  • features of ruby
  • ruby vs other languages
  • rvm
• vim
• ruby style guidelines
• operators
• variables
• data types
• methods, return not needed on last line,
• control statements
• loops, iterations, methods like map, select
• exception handling
• gems, gemsets, creating a gem
• debugging code (usin pry)
• rubocop
• block, proc, lambda
• object oriented concepts
  • why OOPS?
  • a little revision on concepts
  • classes and objects:
    • instance/class vaiables/methods
    • accessor methods
    • self keyword
    • public, private, protected methods
  • inheritance
  • modules:
    • mixins
    • namespacing

https://launchschool.com/books/ruby/read/

Intro:

• It emphasizes the necessity for software to be understood by humans first and computers second.
• a high level language
• interpreted language
• Ruby abstracts away (i.e. handles for you) most of the complex details of the machine
• flexibility
• performance (why it is slower)
• everything is an object

Style guidelines:

• indenting: 2 spaces for a tab
• variable and method names: use snake_case
• CONSTANT declarations
• ClassName: CamelCase
• single line and multiline blocks
• string '' cs ""

Strings:

• interpolation
• escape chars

Symbols

Numbers:

• int, float

Boolean

nil:

• nothing

Operators:

• • • / % == === < > && || !

Type conversion: to_i, to_s etc

Data Strictures:

• Array
• Hash
  • see different methods
  • sequence?

Variables:

• assigninig values

• CONSTANTS

• $global_variables

• scope of variables

Methods:

• why?
• how in ruby
• params, arguments
• default arguments
• variable scope in methods
• method chaining
• methods as arguments?

Conditionals:

• if else unless
• ternary
• switch case

---

Questions:

• Difference between "string" and "symbol" in ruby?

• What is "nil" in ruby, is it an object?

• Difference between "nil" and empty string ""?

• Difference between "==" and "==="

• Difference between single quote and double quote

• [ a = "hi there" b = a a = "not here" puts b ]

  [ a = "hi there" b = a a << ", Bob" puts b ]

  • what is the value of b printed in each of the above?
  • why?

Ruby: Day 2

• prev day assignments

• revision of day 1

• what anyone learnt new that wasn't taught

• comparing two hashes?

• other ways to create a Hash/Array

  • using new keyword

• scopes of variables

• global variables

• default params for a method

• methods as arguments?

• variable number of parameters for a method (*)

• undef method

• Range in ruby:

  • use to_a method

  • as sequences:

    digits = 0..9 puts digits.include?(5) ret = digits.min digits.each {|n| puts n }
  • as conditions: case when 0..30
  • as intervals (1..10) === 5

• loops in ruby

  • while do...end
  • begin..end while
  • until do..end
  • for in for num in 1..5 { num }
  • break and next statements
  • each do..end

• extra Array methods:

  • sort
  • select
  • collect a = [1,2,3,4,5] b = a.collect{|x| 10*x}
  • map

• extra Hash methods:

  • clear, delete, each, each_key, empty?, has_value?(value), inverse, keys, merge, merge!, reject, select, sort, to_a,

• blocks in ruby

  • passing a block to a method (a block that accepts params)
  • calling the block in the method using yield
    • def test yield end test { puts "Hello world"}
  • other way to call the block in the method
    • def test(&block) block.call end test { puts "Hello World!"}`

• Exceptions: begin
  # -
  rescue OneTypeOfException
  # -
  rescue AnotherTypeOfException
  # -
  else
  # Other exceptions ensure # Always will be executed end

• inheritance: (IS-A)

  • overriding
  • super keyword
  • private methods
  • protected methods

• modules: (HAS-A)

  • why?

  • including

  • extending

  • no instantiation

  • order of including modules important?

  • a way to achieve multiple inheritance?

  • the diamond problem

  • namespacing: (organizing similar classes in a module)

    • defining classes inside a module

Sample Conceptual questions to be asked:

(Questions that may need some exploring on their own)

• Difference between "string" and "symbol" in ruby?

• What is "nil" in ruby, is it an object?

• Difference between "nil" and empty string ""?

• Difference between "==" and "==="

• Difference between single quote and double quote

• How can we access/set value for a variable which is declared inside class but outside every method...????

• In Ruby, if a class itself is an object, then how can we access the properties/attributes of that object..???

• Can we create nested modules..?? If yes, then how they can be used..?? Study the syntaxes...

• How can we access the CONSTANTS declared inside Module or Class, outside Module/Class...????

• Differentiate between block, proc and lambda, when to use which.

• [ a = "hi there" b = a a = "not here" puts b ]

  [ a = "hi there" b = a a << ", Bob" puts b ]

  • what is the value of b printed in each of the above?
  • why?