Ruby Basics: Ruby in 100 minutes or less

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ruby basics As much Ruby as Liz can teach you in >100 minutes.

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hey girl hey! um, who are you? I am a very nice person who loves tacos.

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workshop info puts ‘hello, beginners!’

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code conventions

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text editor is pink # taco.rb taco = “yummy” puts taco

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terminal is green $ ruby taco.rb # => “yummy” ! $ ruby --v

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Exercises! • Some slides will have bullets on them. • These bullets will tell you what to do. • You should listen to the bullets... • or you won’t learn anything. • Who run the world? • Girls. Beyoncé. Me. Bullets.

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two ways to run ruby

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irb your file $ irb $ puts “hello world” # => “hello world” $ exit ! ! # hello.rb puts “hello taco” ! $ ruby hello.rb # => “hello taco”

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variables

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variables a = 1 variable value

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variable names YES ! hello_taco taco5000 ! NO! 99bottles 144324322 extra-chz taco’s?!  WAT ? TACO Party

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numbers

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ruby can math! # hello.rb a = 1 b = 2 c = a + b puts a + b puts c $ ruby hello.rb # => 3 # => 3

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what is d? a = 5 b = 10 c = 2 d = c * a - b what is d?

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exercise: such math • Assign some numbers to variables and do some math. • Write code in irb or save your file and run with terminal. • What happens when you combine operators? • What happens when you use decimals? • Do you get any unexpected results? * * try and blow it up

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modulo # hello.rb puts 10 % 5 puts 10 % 3 ! $ ruby hello.rb # => 0 # => 1

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strings

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strings # hello.rb first_name = ‘Liz’ last_name = ‘Abinante’ name = first_name + ‘ ’ + last_name name_alt = “#{first_name} ‘The Taco’ #{last_name}” puts name puts name_alt

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strings $ ruby hello.rb # => Liz Abinante # => Liz ‘The Taco’ Abinante

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strings # hello.rb age = ‘28’ puts name + ‘ is ’ + age ! ! ! $ ruby hello.rb # => Liz Abinante is 28

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exercise: very variable • Create the following variables and assign them values: • age, name, city, favorite_color, favorite_food • Use concatenation or interpolation to create new variables.* • What do you expect? What do you get? • What happens when you do this? puts name * 15 * VARIABLE-CEPTION.

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playinG with strings (nicely)

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BANG BANG ! Strings in Ruby are mutable. Lots of String class methods have destructive and non-destructive counterparts. my string class method shot me dooowwwnnn.

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.delete & .delete! me = “Liz” me.delete(“z”) # => “Li” puts me #=> “Liz” ! me.delete!(“z”) #=> “Li” puts me #=> “Li”

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.swapcase & .swapcase! me = “Liz” me.swapcase # => “lIZ” puts me #=> “Liz” ! me.swapcase! #=> “lIZ” puts me #=> “lIZ”

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.reverse & .reverse! party = “all the time” party.reverse! # => “emit eht lla” puts party # => “emit eht lla”

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<< letters = “abc” letters << “domino” puts letters # => “abcdomino”

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arrays

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arrays things_in_tacos = [“cheese”, “guacamole”] things_in_salsa = [“lime juice”, “mangos”] ! ! ! ! things_in_my_belly = [things_in_salsa, things_in_tacos, “ice cream”]

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arrays: length array = [“chickens”, “two cents”, “ke$ha”] ! array.length # => 3

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arrays: index array = [“chickens”, “two cents”, “ke$ha”] array[0] array[2] array[1]

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arrays: new items taco = [“cheese”, “guacamole”] taco << “sour cream” taco << “potato chips” << “jelly beans” # => [“cheese”, “guacamole”, “sour cream”, “potato chips”, “jelly beans”]

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playing with arrays (nicely... sometimes)

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booleans

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nil

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methods

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you already know what a method is. All that stuff we did to strings and arrays? Those were methods.

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methods: return values def taco “tacos are delicious” end ! puts taco # => “tacos are delicious”

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passing arguments def say_hi_to(name) “Hello #{name}!” end ! puts say_hi_to(“Buffy Summers”) # => “Hello Buffy Summers!”

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more arguments def salutations(greeting, name) “#{greeting}, #{name.upcase}.” end ! puts salutations(“Goodbye”, “Angel”) # => “Goodbye, ANGEL.”

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multi-line methods def introduce(name, food) greet = “Hello, this is #{name}. ” yummy = “#{name}’s favorite food is #{food}.” greet + yummy end puts introduce(“Liz”, “TACOS”) # => “Hello, this is Liz. Liz’s favorite food is TACOS.”

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more on return values def fail_introduce(name, food) greet = “Hello, this is #{name}. ” return greet yummy = “#{name}’s favorite food is #{food}.” greet + yummy end puts fail_introduce(“Liz”, “ALL THE TACOS”)

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exercise: write methods • Write a method that takes more than 1 argument and returns a sentence composed of all the arguments. • Write a method that uses modulo. • Write a multiple-line method with a return statement. • Write a method that takes an array as an argument. * * YOU SO FANCY.