plusor

在Programming Ruby 书中介绍block的时候提到过. 花括号比do..end绑定更为严密.

花括号

puts (1..10).map {|i| i * 2}
2
4

plusor

• db:create creates the database for the current env
• db:create:all creates the databases for all envs
• db:drop drops the database for the current env
• db:drop:all drops the databases for all envs
• db:migrate runs migrations for the current env that have not run yet
• db:migrate:up runs one specific migration
• db:migrate:down rolls back one specific migration
• db:migrate:status shows current migration status
• db:migrate:rollback rolls back the last migration
• db:forward advances the current schema version to the next one

plusor

---

Class Name corresponds to

Module      included

plusor

异常信息(Exception Information)

                                     #传递给raise的异常对象.
$!                Exception          #The exception object passed to raise. [thread]
                                     #最后一个异常产生时的调用栈. 详见 Kernel#caller.
$@                Array              #The stack backtrace generated by the last exception. See Kernel#caller. [thread] 

plusor

Ensures that the object/expression is true.

• assert( boolean, [msg] )

---

Ensures that obj1 == obj2 is true.

• assert_equal( obj1, obj2, [msg] )

plusor

alias 和 alias_method 区别 ruby

1

class User

  def full_name

plusor

/(?<foo>regexp)/ =~ "regexp"

foo # => "regexp"

plusor

class Foo
  include MagicEnum
  attr_accessor :status

  enum_attr :status, [ ["Open",0],["Close",1]]
end

foo = Foo.new
foo.status = 1

plusor

class Hash
  #   k = {}
  #   k.create_deeps(*%w(1 2 3 4 5 6 7 8 9 10))
  #   #=> {"1"=>{"2"=>{"3"=>{"4"=>{"5"=>{"6"=>{"7"=>{"8"=>{"9"=>"10"}}}}}}}}}
  def create_deeps(*args)
    self.replace deep_create(*args)
  end
  
  def deep_create(*args)
    dup.deep_create!(*args)

plusor

class Area < ActiveRecord::Base
  acts_as_nested_set :counter_cache => :children_count
  #Area.rebot(省ID,[市ID])
  #Area.rebot(3198,[3213]) or Area.rebot(3198)
  scope :robot, ->(s,q=[]) { where("parent_id in (?)",q.or(select(:id).where(:parent_id => s))) }

  [:parent,:root,:province,:city,:district].each do |instance|
      class_eval <<-EOF,__FILE__,__LINE__ + 1
        delegate :name,:to => :#{instance} ,:allow_nil => true,:prefix => true
        #{next if [:parent].include?(instance)}