Introduction to Ruby (Rails Girls)

A short introduction to Ruby, created with one of the Rails Girls events in mind.

It tries to cover variables, simple calculations, conditions, functions, collections, symbols and classes.

Transcript

1. Introduction to Ruby Łukasz Wróbel
2. About me • Architect, team leader; • high-traffic websites: ◦ nk.pl; ◦ Gadu-Gadu. • “Memoirs of a Software Team Leader”; • @lukaszwrobel
3. Agenda Ain't nobody got time for that! Pure essence.
4. Computers are like guys Do this, then do that. Be precise.
5. Say hello!
6. puts "Hello, world!"
7. Variables
8. message = "Hello world!" puts message
9. Calculations
10. puts 5 + 3 * 2
11. puts 5 + 3 * 2 # => 16?
12. puts "H" + "ello"
13. Conditions
14. age = 22 if age > 30 puts "Too old" else puts "Acceptable" end
15. Repetitions
16. puts "Hello, John" puts "Hello, Mary" puts "Hello, everyone"
17. Functions to the rescue!
18. def say_hello(name) puts "Hello, " + name end
19. say_hello("John") say_hello("Mary") say_hello("everyone")
20. say_hello("John") say_hello("Mary") say_hello("everyone") # => "Hello, John" # => "Hello, Mary" # => "Hello, everyone"
21. Introducing changes
22. def say_hello(name) puts "Hello, " + name + "!" end
23. Collections
24. names = ["John", "Mary", "everyone"] names.each do |name| say_hello(name) end
25. Plus a few nice features
26. prices = [100, 9.99, 14] prices.reduce(:+)
27. prices = [100, 9.99, 14] prices.reduce(:+) # => 123.99
28. Filtering
29. [9, 5, 3, 4, 7].find_all {|number| number > 5} # => [9, 7]
30. Mapping
31. ["These", "are", "words"].map {|word| word.upcase} # => ["THESE", "ARE", "WORDS"]
32. Hashes
33. friend = { "name" => "William", "age" => 45, } puts friend["name"] # => "William"
34. Symbols Unique. More common.
35. friend = { :name => "William", :age => 45, } puts friend[:name] # => "William"
36. Classes
37. class Person def say_hello(name) puts "My name is " + name end end somebody = Person.new somebody.say_hello("Emily")
38. somebody = Person.new somebody.say_hello("Emily") somebody.say_hello("Somebody else") somebody.say_hello("Whatever")
39. Not only methods, but also data
40. class Person def initialize(name) @name = name end def say_hello puts "My name is " + @name end end me = Person.new("Łukasz") me.say_hello # => "My name is Łukasz"
41. It’s just the beginning.
42. Thank you! @lukaszwrobel