我不明白为什么下面不工作:文件的红宝石方法未定义nilClass错误的字符串方法
#TODO:
#Open file-io-samples/MultipleLinesCustomDelimiter.txt
#Break each line into fields
#Convert Times from mm:ss to seconds
#Remove any redundant spaces.
#######################################################
Song = Struct.new(:title, :name, :length)
File.open("file-io-samples/MultipleLinesCustomDelimiter.txt") do |file_data|
songs = []
file_data.each do |line|
file, length, name, title = line.chomp.split(/\s*\|\s*/)
name.squeeze!(" ") #Error: undefined method for nilClass
mins, secs = length.scan(/\d+/) #Error: undefined method for nilClass
secs += mins*60
songs << Song.new(title, name, secs)
end
puts songs[1] #make sure output is consistent.
end
内容多数民众赞成读取:
/jazz/j00132.mp3 | 3:45 | Fats Waller | Ain't Misbehavin'
/jazz/j00319.mp3 | 2:58 | Louis Armstrong | Wonderful World
/bgrass/bg0732.mp3| 4:09 | Strength in Numbers | Texas Red
: : : :
这是一个来自Programming Ruby书籍的例子。我不知道为什么scan方法和squeeze方法在字符串对象不是nilClass对象时抛出错误。如果没有这些,put songs [1]的输出看起来是正确的。
他们说他们是'nilClass',不'String'。 – sawa
我知道,但我不明白他们如何不能串。 – Senjai