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2018年09月07日 ⁄ 综合 ⁄ 共 2005字 ⁄ 字号小中大 ⁄ 评论关闭

1.to_proc

class Array
  def to_proc
    proc { |receiver| receiver.send *self }
  end
end


[ 'Hello', 'Goodbye' ].map &[ :+, ' BeiJing!' ]

#=> ["Hello BeiJing!", "Goodbye BeiJing!"]

receiver -> [ 'Hello', 'Goodbye' ]

*self -> [ :+, ' BeiJing!' ]

2.map(&:key)

order_records = OrderRecord.all(:all, :limit => 10)

order_records.map(&:order_no)

#=> ["20140627141050-5096zG", "20140627143533-90bm9v", "20140627143648-2sJQxR", "20140627161046-UE0y07", "20140627161456-16GGT1", "20140627161707-58Lc3t", "20140627173915-0mI1Ji", "20140627175248-31YTtk", "20140627180802-s487cX", "20140717112957-eQ993g"]

arr = '100+100+200+100'

arr.split('+').map(&:to_i)

3.hash = JSON.parse content.gsub!('=>', ':')

require 'rubygems'
require 'json'

content = %Q({\"credentials\"=>{\"token\"=>\"F538FF45937887AF7246E50928E0961F1\", \"refresh_token\"=>\"6EC400DD7B547B401D29474EA68952145\", \"expires_at\"=>1418310654, \"expires\"=>true}})

hash = JSON.parse content.gsub!('=>', ':')

4.好有创意

http://www.zcool.com.cn/special/znote2014/

5.对 define_method， instance_variable_get，instance_variable_set 的使用

class Activity
  attr_reader :data
  
  def self.<< data
    new(data).call
  end

  def self.data_reader *attrs
    
    attrs.each do |attr|
      define_method attr do
        instance_variable_get("@#{attr}") || \
        instance_variable_set("@#{attr}", data[attr.to_sym])
      end
    end
    
  end

  def self.default attr, default
    orig_attr = "#{attr}_without_default"
    alias_method orig_attr, attr
    define_method attr do
      send(orig_attr) || default
    end
  end

  def self.set name, value

    if value.is_a? Symbol
      define_method name do
        instance_variable_get("@#{name}") || \
        instance_variable_set("@#{name}", send(value) )
      end
    elsif value.respond_to? :call
      define_method name do
        instance_variable_get("@#{name}") || \
        instance_variable_set("@#{name}", value.call)
      end
    else
      define_method name do
        instance_variable_get("@#{name}") || \
        instance_variable_set("@#{name}", value)
      end
    end
    
  end

  def initialize(data = {})
    @data = data
  end
  
  def call
    ''
  end

  private
  def set(name,value)
    instance_variable_set("@#{name}", value)
  end

  def get_or_set(name)
    value = instance_variable_get("@#{name}")
    return value if value
    value = yield
    instance_variable_set("@#{name}", value)
  end

end