# case_when_matcher_classes.rb

class Zigor
  def self.===(string)
    string.downcase == "zigor"
  end
end

name = "Zigor"

case name
when Zigor
  puts "Nice to meet you Zigor!!!"
else
  puts "Who are you?"
end

10.downto 1 do |num|
  p num
end

17.upto 23 do |i|
  print "#{i}, "
end

1.step 10 do |i|
 print "#{i}, "
end
# 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,

10.step 1 do |i|
 print "#{i}, "
end

#10, 9, 8, 7, 6, 5, 4, 3, 2, 1,

10.step 1, -2 do |i|
  print "#{i}, "
end
# 10, 8, 6, 4, 2, 

2.step 10, 2 do |i|
  print "#{i}, "
end
# 2, 4, 6, 8, 10,

redo:

5.times do |num|
  puts "num = #{num}"
  puts "Do you want to redo? (y/n): "
  option = gets.chop
  redo if option == 'y'
end

array

dig

>> array = [1, 5, [7, 9, 11, ["Treasure"], "Sigma"]]
=> [1, 5, [7, 9, 11, ["Treasure"], "Sigma"]]
>> array.dig(2, 3, 0)
=> "Treasure"
=> array[2][3][0]
>> "Treasure"

array

>> volleyball=["Ashok", "Chavan", "Karthik", "Jesus", "Budha"]
=> ["Ashok", "Chavan", "Karthik", "Jesus", "Budha"]
>> cricket=["Budha", "Karthik", "Ragu", "Ram"]
=> ["Budha", "Karthik", "Ragu", "Ram"] 

>> volleyball & cricket
=> ["Karthik", "Budha"] 

>> volleyball | cricket
=> ["Ashok", "Chavan", "Karthik", "Jesus", "Budha", "Ragu", "Ram"] 

>> volleyball + cricket
=> ["Ashok", "Chavan", "Karthik", "Jesus", "Budha", "Budha", "Karthik", "Ragu",
"Ram"]

>> volleyball - cricket 
=> ["Ashok", "Chavan", "Jesus"]

作用域

$x = 5
def print_x
    $x = 3
    puts $x
end
print_x
puts $x
# 3
# 3

对象

class Square
    attr_accessor :side_length
    def initialize side_length = 0
        @side_length = side_length
    end
    def area
        @side_length * @side_length
    end
    def perimeter
        4 * @side_length
    end
end

s1 = Square.new 4
s2 = Square.new
s2.side_length = 5
puts "Area of s1 is #{s1.area} squnits"
puts "Peimeter of s2 is #{s2.perimeter} units"
Output
Area of s1 is 16 squnits
Perimeter of s2 is 20 units

chmod a+x shebang.rb