ruby的hash學習筆記例： 將字串文字中的單詞存放在map中

c3tc3tc3t發表於2015-12-01
筆記字串
text = 'The rain in Spain falls mainly in the plain.'
first = Hash.new []
second = Hash.new  {|hash,key| hash[key] = []}


text.split(/\W+/).each do |word|
  p "word: #{word}"
  p first[word[0, 1].downcase].object_id
  first[word[0, 1].downcase] << word
  p first[word[0, 1].downcase]
end
p first

"word: The"
46999283958220  這裡是關鍵。每次都是引用同一個陣列。
["The"]
"word: rain"
46999283958220
["The", "rain"]
"word: in"
46999283958220
["The", "rain", "in"]
"word: Spain"
46999283958220
["The", "rain", "in", "Spain"]
"word: falls"
46999283958220
["The", "rain", "in", "Spain", "falls"]
"word: mainly"
46999283958220
["The", "rain", "in", "Spain", "falls", "mainly"]
"word: in"
46999283958220
["The", "rain", "in", "Spain", "falls", "mainly", "in"]
"word: the"
46999283958220
["The", "rain", "in", "Spain", "falls", "mainly", "in", "the"]
"word: plain"
46999283958220
["The", "rain", "in", "Spain", "falls", "mainly", "in", "the", "plain"]
{}

 



text.split(/\W+/).each do |word|
  p "word: #{word}"
  p second[word[0, 1].downcase].object_id
  second[word[0, 1].downcase] << word
  p second[word[0, 1].downcase]
end
p second
"word: The"
46999283949940
["The"]
"word: rain"
46999283924940  這裡按照key取，不同的key對應不同的陣列
["rain"]
"word: in"
46999283924440
["in"]
"word: Spain"
46999283923920
["Spain"]
"word: falls"
46999283923420
["falls"]
"word: mainly"
46999283922920
["mainly"]
"word: in"
46999283924440
["in", "in"]
"word: the"
46999283949940
["The", "the"]
"word: plain"
46999283921440
["plain"]
{"t"=>["The", "the"], "r"=>["rain"], "i"=>["in", "in"], "s"=>["Spain"], "f"=>["falls"], "m"=>["mainly"], "p"=>["plain"]}

 



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