>> a = "abc"
#=> "abc"

>> b = a + ""
#=> "abc"

?> a == b
#=> true

>> a.object_id
#=> 70255156346640

>> b.object_id
#=> 70255156340640

case some_object
when /a regex/
 # The regex matches
when String
 # some_object is kind of String
when 2..4
 # some_object is in the range 2..4
when lambda {|x| some_crazy_custom_predicate }
 # the lambda returned true
end

if /a regex/ === some_object
 # The regex matches
elsif String === some_object
 # some_object is kind of object
elsif (2..4) === some_object
 # some_object is in the range 2..4
elsif lambda {|x| some_crazy_custom_predicate } === some_object
 # the lambda returned true
end

1 == 1.0  #=> true
1.eql? 1.0 #=> false

[1] pry(main)> hash = Hash.new
#=> {}
[2] pry(main)> hash[2] = "a"
#=> "a"
[3] pry(main)> hash[2.0] = "b"
#=> "b"
[4] pry(main)> hash[2]
#=> "a"
[5] pry(main)> hash[2.0]
#=> "b"
[6] pry(main)> hash[2.00] = "c"
#=> "c"
[7] pry(main)> hash[2.0]
#=> "c"

q = User.first
 User Load (40.4ms) SELECT "users".* FROM "users"  ORDER BY "users"."id" ASC LIMIT 1
#=> #<User id: 1, email: "ryan@wongyouth.com">

q2 = User.first
 User Load (0.4ms) SELECT "users".* FROM "users"  ORDER BY "users"."id" ASC LIMIT 1
#=> #<User id: 1, email: "ryan@wongyouth.com">

q.equal? q2
#=> false