Question

我的应用程序需要从文件中读取数据，然后用户可以搜索该数据以查看其是否存在。该文件读取相册的ID，然后用户必须输入该ID才能访问它

文本文件

Marcus Hospin
Raw
3 - Genre Value
1 - ID 
Sag My Pants
sounds/01-Sag-My-Pants.wav
The Purge
sounds/06-The-Purge.wav
Ill Mind 8
sounds/20-Ill-Mind-8.wav

红宝石代码

class Album
  attr_accessor :title, :artist, :genre, :id, :tracks

  def initialize (title, artist, genre, id)
    @title = title
    @artist = artist
    @genre = genre
    @id = id

  end
end

def read_album(music_file)
  album_artist = music_file.gets
  album_title = music_file.gets
  album_genre = music_file.gets
  album_id = music_file.gets
  album = Album.new(album_title, album_artist, album_genre, album_id)
  album
end

def main
album = read_album(music_file)
puts 'Enter the ID of the album you wish to play'
      search_string = gets.to_s
      album.map(&:id).include?(search_string) || -1
      if index != -1
        puts "Found, playing album " + album[index].id + " at " + index.to_s
      else
        puts "Entry not Found"
      end
end

main

程序的预期结果是返回“找到，正在1（索引）播放专辑1（ID）。但是实际输出是undefined method `map' for #<Album:0x0000000003357ca0> (NoMethodError)

Answer 1

map是未定义的，因为您在单个对象而不是对象集合上调用它。您需要先用Album个对象填充数组，然后才能map对其进行覆盖。

搜索值是否存在

1 个答案: