第一个ruby程序中遇到的问题

使用ruby语言编程的感觉是，一次又一次的惊叹，非常神奇有人竟然把我之前用c、c++等语言编程时所遭遇的痛苦一次又一次地抚平。

下面这段代码是我照教材敲出来的(summarize.rb)，用于从一段文本中选择包含感兴趣的句子。

text =%q{
Ruby is a great programming language. It is object oriented
and has many groovy features. Some people don't like it, but
that's not our problem!It's easy to learn. It's great.To learn
more about Ruby,visit the official Ruby Web site today.
}

sentences =text.gsub(/\s+/, ' ').strip.split(/\.|\?|!/)
sentences_sorted =sentences.sort_by {|sentence| sentence.length}
one_third =sentences_sorted.length /3
ideal_sentences =sentences_sorted.slice(one_third, one_third +1)
ideal_sentences =ideal_sentences.select { |sentence| sentence =~ /is|are/ }
puts ideal_sentences.join(".")

#ruby summarize.rb运行之后，弹出一个bug：summarize.rb:12: syntax error, unexpected '}'。

但是检查数遍，也没看出个所以然。倒是将one_third直接赋常量后，就OK了。继续找找原因吧。