Ruby文件处理、读取然后作为数组存储

我无法理解这段代码是如何工作的，程序能够读取文件，但最终会多次打印同一行

输出：

Track title is: c/music/1

Track file location is: c/music/1

Track title is: c/music/2 

Track file location is: c/music/2

Track title is: c/music/3

Track file location is: c/music/3

Track title is: Taco

Track file location is: c/music/1

Track title is: Burrito 

Track file location is: c/music/2

Track title is: Nacho

Track file location is: c/music/3

class Track
    attr_accessor :title, :file_location
end

def read_tracks music_file

    count = music_file.gets().to_i
  tracks = Array.new
  $i = 0

  while $i < count do
  track = read_track(music_file)
  tracks << track
  $i += 1
  end
    tracks
end


def read_track aFile

  track_title = aFile.gets
  track_file_location = aFile.gets
  track = Track.new
  track.title = track_title
  track.file_location = track_file_location

end



def print_tracks tracks
  $i = 0
  while $i < tracks.length do
    print_track(tracks)
    $i += 1
  end

end


def print_track tracks
  puts('Track title is: ' + tracks[$i].to_s)
    puts('Track file location is: ' + tracks[$i].to_s)
end


def main
  aFile = File.new("input.txt", "r") 
  if aFile  
    tracks = read_tracks(aFile)
    aFile.close
  else
    puts "Unable to open file to read!"
  end

  print_tracks(tracks)
end

main

5

Taco

c/music/1

Burrito

c/music/2

Nacho

c/music/3

预期输出：

Track title is: c/music/1

Track file location is: c/music/1

Track title is: c/music/2 

Track file location is: c/music/2

Track title is: c/music/3

Track file location is: c/music/3

Track title is: Taco

Track file location is: c/music/1

Track title is: Burrito 

Track file location is: c/music/2

Track title is: Nacho

Track file location is: c/music/3

class Track
    attr_accessor :title, :file_location
end

def read_tracks music_file

    count = music_file.gets().to_i
  tracks = Array.new
  $i = 0

  while $i < count do
  track = read_track(music_file)
  tracks << track
  $i += 1
  end
    tracks
end


def read_track aFile

  track_title = aFile.gets
  track_file_location = aFile.gets
  track = Track.new
  track.title = track_title
  track.file_location = track_file_location

end



def print_tracks tracks
  $i = 0
  while $i < tracks.length do
    print_track(tracks)
    $i += 1
  end

end


def print_track tracks
  puts('Track title is: ' + tracks[$i].to_s)
    puts('Track file location is: ' + tracks[$i].to_s)
end


def main
  aFile = File.new("input.txt", "r") 
  if aFile  
    tracks = read_tracks(aFile)
    aFile.close
  else
    puts "Unable to open file to read!"
  end

  print_tracks(tracks)
end

main

5

Taco

c/music/1

Burrito

c/music/2

Nacho

c/music/3

代码：

Track title is: c/music/1

Track file location is: c/music/1

Track title is: c/music/2 

Track file location is: c/music/2

Track title is: c/music/3

Track file location is: c/music/3

Track title is: Taco

Track file location is: c/music/1

Track title is: Burrito 

Track file location is: c/music/2

Track title is: Nacho

Track file location is: c/music/3

class Track
    attr_accessor :title, :file_location
end

def read_tracks music_file

    count = music_file.gets().to_i
  tracks = Array.new
  $i = 0

  while $i < count do
  track = read_track(music_file)
  tracks << track
  $i += 1
  end
    tracks
end


def read_track aFile

  track_title = aFile.gets
  track_file_location = aFile.gets
  track = Track.new
  track.title = track_title
  track.file_location = track_file_location

end



def print_tracks tracks
  $i = 0
  while $i < tracks.length do
    print_track(tracks)
    $i += 1
  end

end


def print_track tracks
  puts('Track title is: ' + tracks[$i].to_s)
    puts('Track file location is: ' + tracks[$i].to_s)
end


def main
  aFile = File.new("input.txt", "r") 
  if aFile  
    tracks = read_tracks(aFile)
    aFile.close
  else
    puts "Unable to open file to read!"
  end

  print_tracks(tracks)
end

main

5

Taco

c/music/1

Burrito

c/music/2

Nacho

c/music/3

---

问题在于方法打印轨道和打印轨道
这些方法应该如下所示：

def print_tracks tracks
  $i = 0
  while $i < tracks.length do
    print_track(tracks[$i])
    $i += 1
  end    
end


def print_track track
  puts('Track title is: ' + track.title.to_s)
    puts('Track file location is: ' + track.file_location.to_s)
end

def print_tracks(tracks)
  tracks.each do |track|
    puts "Track title is: #{track.title}"
    puts "Track file location is: #{track.file_location}"
    puts
  end
end

在这种情况下，整个代码将为：

class Track
  attr_accessor :title, :file_location
end

def read_tracks music_file
  count = music_file.gets().to_i
  tracks = Array.new
  i = 0

  while i < count do
    track = read_track(music_file)
    tracks << track
    i += 1
  end

  tracks
end

def read_track aFile
  track = Track.new
  track.title = aFile.gets
  track.file_location = aFile.gets
  track
end

def print_tracks(tracks)
  tracks.each do |track|
    puts "Track title is: #{track.title}"
    puts "Track file location is: #{track.file_location}"
    puts
  end
end

def main
  aFile = File.new("input.txt", "r").
  if aFile..
    tracks = read_tracks(aFile)
    aFile.close
  else
    puts "Unable to open file to read!"
  end

  print_tracks(tracks)
end

main

我得到了输出：

Track title is: Taco
Track file location is: c/music/1

Track title is: Burrito
Track file location is: c/music/2

Track title is: Nacho
Track file location is: c/music/3

---

这正是你所期望的

尝试此操作，将线覆盖到阵列，然后对其进行操作：

lines = File.readlines('tracks.txt') # reads lines into array
lines.reject! { |e| e == "\n" } # removes empti lines
total_tracks = lines.shift.chomp.to_i # extract the first line from the array
lines.each_slice(2) { |e| puts e } # lines now contains only the pair track/directory
# adapt at your will

---

对于

每个\u片段（2）

请参见，它将数组的元素分组。

在输入文本文件中，我们是否可以假设每个曲目信息位于新行上？你能发布输入文件的示例吗？另外，您可以发布一个格式化的输出示例吗？按照您的方式，您似乎希望输出一行文本，而不输出新的文本行。您好，很抱歉这篇文章的格式设置不好。输入文件有7行，第一行包含一个数字，表示“轨迹”的数量。我还需要一个新的行输出。5在输入文件的第一行表示什么？这种模式重复吗？很难理解这个模式是什么。请不要在Ruby中使用全局变量（或者其他任何地方），永远不要。Jörg W Mittag，当我发布解决方案时，我尝试对作者的代码进行最小的更改，以便更容易理解代码的差异。当然，这里不需要全局变量。Jörg W Mittag，我添加了稍微改进的代码版本，只是为了展示它应该是怎样的。嗨，我试过了，但仍然没有得到想要的输出。我认为错误在于读取文件，尤其是将读取的数据存储为数组时。@Pickles，使用新修订的方法print_tracks，程序的输出是什么？