Comment écrire un interrupteur dans Ruby

90

case x when 1..5   "It's between 1 and 5" when 6   "It's 6" when "foo", "bar"   "It's either foo or bar" when String   "You passed a string" else   "You gave me #{x} -- I have no idea what to do with that." end 

87

1 === 1           # => true Fixnum === Fixnum # => false 

obj = 'hello' case obj.class when String   print('It is a string') when Fixnum   print('It is a number') else   print('It is not a string or number') end 

Fixnum === 1 # => true 

obj = 'hello' case obj  # was case obj.class when String   print('It is a string') when Fixnum   print('It is a number') else   print('It is not a string or number') end 

78

case n when 0   puts 'You typed zero' when 1, 9   puts 'n is a perfect square' when 2   puts 'n is a prime number'   puts 'n is an even number' when 3, 5, 7   puts 'n is a prime number' when 4, 6, 8   puts 'n is an even number' else   puts 'Only single-digit numbers are allowed' end 

score = 70  result = case score    when 0..40 then "Fail"    when 41..60 then "Pass"    when 61..70 then "Pass with Merit"    when 71..100 then "Pass with Distinction"    else "Invalid Score" end  puts result 

67

case a when 1   puts "Single value" when 2, 3   puts "One of comma-separated values" when 4..6   puts "One of 4, 5, 6" when 7...9   puts "One of 7, 8, but not 9" else   puts "Any other thing" end 

case when b < 3   puts "Little than 3" when b == 3   puts "Equal to 3" when (1..10) === b   puts "Something in closed range of [1..10]" end 

58

is_even = ->(x) { x % 2 == 0 }  case number when 0 then puts 'zero' when is_even then puts 'even' else puts 'odd' end 

Moddable = Struct.new(:n) do   def ===(numeric)     numeric % n == 0   end end  mod4 = Moddable.new(4) mod3 = Moddable.new(3)  case number when mod4 then puts 'multiple of 4' when mod3 then puts 'multiple of 3' end 

class Vehicle   def ===(another_vehicle)     self.number_of_wheels == another_vehicle.number_of_wheels   end end  four_wheeler = Vehicle.new 4 two_wheeler = Vehicle.new 2  case vehicle when two_wheeler   puts 'two wheeler' when four_wheeler   puts 'four wheeler' end