Successfully reported this slideshow.
Your SlideShare is downloading. ×

Ruby basic

Advertisement

More Related Content

Advertisement

Ruby basic

  1. 1. Ruby Basic(1) Author: Jason
  2. 2. Content Feature String Array Hash Symbol Control Struct
  3. 3. Feature Nearly 100% Object-Oriented Dynamic No need to compile
  4. 4. Object-oriented 1.class # => Fixnum 1.2.class # => Float true.class # => TrueClass
  5. 5. Dynamic a = "String abc" a.class # => String a = 10 a.class # => Fixnum
  6. 6. No need to compile Enter irb in cmd/terminal play with Ruby!!
  7. 7. String types Single quote Just to store character Better in performance Double quote Store binary value, eg: n Execute Ruby code in #{}
  8. 8. String Example v = "double" s = 'I am a single quote String' # => "I am a single quote String" s = "I am a #{v} quote String" # => "I am a double quote String" #{} is to execute the ruby code
  9. 9. Array(1) Contain a list of item The elements can be any type a = [1, 'count', 3.14] a[0] # => 1 a[-1] # => 3.14
  10. 10. Array(2) Short cut to create String Array: a = %w{jason sam ray} a # => ["jason", "sam", "ray"]
  11. 11. Hash Similar to associative array Key & Value score = {'jason' => 10, 'ray' => 9, 'sam' => 1} score['jason'] # => 10
  12. 12. Symbol(1) They are String Use as identify Unique in value (handled by Ruby) Same object id All methods and variables have its own symbol
  13. 13. Symbol(2) In Java, we define somethings like int NORTH = 1 int EAST = 2 In Ruby you just use :north, and :east to act as identify, they should be unique in value
  14. 14. Unique in value n = :north n2 = :north if n == n2 puts "n is equal to n2" end • Results : n is equal to n2
  15. 15. Same object ID n = :north n2 = :north n.object_id # => 292808 n2.object_id # => 292808
  16. 16. Symbol in Hash Symbol usually acts as key in hash to save memory. Ruby 1.8: score = {:jason => 10, :ray =>4, :sam => 1} Ruby 1.9, you can also: score = {jason: 10, ray: 4 ,sam: 1} score[:jason] # => 10
  17. 17. Control Structure(1) if jason == 'jason' puts "I am Jason" end
  18. 18. Control Structure(2) if jason == 'jason' puts "I am not Jason" else puts "I am Jason" end
  19. 19. Control Structure(3) if jason == 'jason' puts "I am not Jason" elsif jason == 'handsome' puts "Jason is handsome" else puts "I am Jason" end
  20. 20. Control Structure(4) while jason < 100 and jason > 50 jason = jason +1 end and is equal to && or is equal to ||

×