我的第一份Ruby代码

require 'date'

#
# 定义常量 MY_BOOK
#
# @param [Array]
MY_BOOK = [
  {
    title: '台湾自助游参考手册',
    describe: '从此告别跟团的强制购物',
    book_type: '1',
    price: '50',
    published_at: '2014-01-01 01:01:01'
  },
  {
    title: 'Ruby完全入自学册',
    describe: 'Ruby入门必读精品',
    book_type: '2',
    price: '75',
    published_at: '2015-02-02 02:02:02'
  },
  {
    title: '军事基础',
    describe: '军事迷必备书籍',
    book_type: '3',
    price: '100',
    published_at: '2016-03-03 03:03:03'
  }
]

class Book
  #
  # 初始化方法
  # @param [String] title 标题
  # @param [String] describe 描述
  # @param [String] book_type 书籍类型
  # @param [String] price 书籍价格
  # @param [String] published_at 发表时间
  #
  # @return [Object] 实例对象
  #
  def initialize(title = '', describe = '', book_type = '0', price = '0', published_at = '')
    @title = title
    @describe = describe
    @book_type = book_type.to_i
    @price = price.to_i
    @published_at = published_at
  end

  #
  # @param [Array] 书籍信息 数组包Hash
  # 
  # @return [Object] 3个实例对象
  #
  def self.create_some_books(args)
    book1 = ::Book.new(args[0][:title], args[0][:describe], args[0][:book_type], args[0][:price], args[0][:published_at])
    book2 = ::Book.new(args[1][:title], args[1][:describe], args[1][:book_type], args[1][:price], args[1][:published_at])
    book3 = ::Book.new(args[2][:title], args[2][:describe], args[2][:book_type], args[2][:price], args[2][:published_at])
    return book1, book2, book3
  end

  #
  # 返回价格等级
  #
  # @param [Integer] 价格
  # 
  # @return [String] 价格等级
  #
  def price_level
    if @price < 60 && @price > 0
      return '低价位'
    elsif @price >= 60 && @price < 90
      return '中价位'
    elsif @price >= 90
      return '高价位'
    end
  end

  #
  # 返回book类型
  # @param [Integer] 1~3 
  # 
  # @return [String] 书籍类型
  # 
  def type_name
    case @book_type
    when 1
      return '1是旅游类'
    when 2
      return '2是技术类'
    when 3
      return '3是军事类'
    else
      return '暂无定义'
    end
  end

  #
  # 循环判断书籍价格 计算价格大于等于60的总数
  # @param [String] 价格
  # 
  # @return [Float] 总价
  # 
  def self.high_price_book_price
    $price_sum = 0
    (0 ... MY_BOOK.length).each do |i|
      if MY_BOOK[i]['price'].to_i >= 60
        $price_sum += MY_BOOK[i]['price'].to_i
      end
    end
    return $price_sum.to_f
  end

  #
  # 循环判断书籍价格， 计算价格大于等于60的平均价格
  # @param [String] 价格
  # 
  # @return [Float] 平均价格
  # 
  def self.avg_price
    $price_avg = 0
    $book_count = 0
    (0 ... MY_BOOK.length).each do |i|
      if MY_BOOK[i][:price].to_i >= 60
        $price_avg += $price_avg + MY_BOOK[i][:price].to_i
        $book_count = $book_count + 1
      end
    end
    return $price_avg.to_f / $book_count
  end

  #
  # 返回某年某月最后一天
  #
  # @param [Integer]] 年
  # @param [Integer] 月
  # 
  # @return [Date] 最后一天的日期
  #
  def self.month_end(year, month)
    date_result = Date.civil(year, month, -1)
    return date_result.day
  end
ß
  #
  # 返回特定格式时间
  #
  # @param [String] 2016-03-03 03:03:03
  #
  # @return [String] 2016年03月03日
  #
  def published_at_cn
    date = Date.parse(@published_at)
    date.year.to_s + '年' + date.month.to_s + '月' + date.day.to_s + '日'
  end
end

# 实例三个对象
@b1, @b2, @b3 = Book.create_some_books(MY_BOOK)

puts @b1.price_level
puts @b1.type_name
puts "大于60总价#{Book.high_price_book_price}"
puts "特定格式日期#{@b1.published_at_cn}"
puts "大于60平均价格#{Book.avg_price}"
puts "最后一天为#{Book.month_end(2016, 2)}"