The document discusses Ruby conditionals including if/else statements, case statements, and unless statements. If/else statements allow executing code conditionally based on boolean expressions. Case statements allow executing different code blocks based on the value of a variable. Unless statements provide a way to check if a condition is false.

1. Conditionals

2. Truth Truth: Everything is true except for: false nil Therefore 0 is true “” is true

3. Conditionals: if if age > 17 puts “can vote” end if age > 17 puts “can vote” else puts “attends school” end Statement Modifiers: do_something if x == 4 Other Syntax: if x == 4 then do_something end

4. Conditionals: if if age >= 21 puts “can drink” elsif age > 17 puts “can vote” else puts “too young” end

5. Checking for false if !(name == “superman”) … if not (name == “superman”) …

6. Unless “unless” provides us with another way of checking if a condition is false: unless human status = "superhero" end status = "superhero" unless human

7. Case case superhero when "superman" city = "metropolis" when "batman" city = "gotham_city" else city = "central_city" end

8. Case Refactoring city = case superhero when "superman" "metropolis" when "batman" "gotham_city" else "central_city" end

9. Case case num when 1 puts "one" when 2..5 puts "that is small" else puts "pretty big" end

10. Case case name when "Sarah" puts "awesome" when /Mr.*/ puts "formal guy" else puts "whatever" end

11. Case case args when String puts "Got a String" when Array puts "Got an Array” when Hash puts "Got a Hash" end