Question

目标是将每个字母移动到字母表中的下一个字母，在地图中，它成功地改变了字母但是一旦我离开那里，除了元音之外，价值消失了。怎么会？

def LetterChanges(str)
  abc = [*("a".."z")]

  result = str.split(//)

  result.map! do |x| 

  if abc.include?(x)

    if x == "z"
       x = "A"
       else
       x = abc[abc.index(x)+1]

       # if you puts x here, you can see it changes value correctly

       if x == "a" || x == "e" || x == "i" || x == "o" || x == "u"
          x.capitalize!
          end
       end
    end

    #However here, the changed values that are not vowels disappear 
    # WHY is that happening, is the second if (vowel) affecting it? How?

end
puts "#{result.join}"  #<--- its only putting the vowels
return result.join  

end

LetterChanges("what the hell is going on?")

Answer 1

传递给map!的块需要在所有情况下都返回一个值才能生效。

http://www.ruby-doc.org/core-2.2.0/Array.html#method-i-map-21

def LetterChanges(str)
  abc = [*("a".."z")]

  result = str.split(//)

  result.map! do |x| 
    if abc.include?(x)
      if x == "z"
         x = "A"
      else
         x = abc[abc.index(x)+1]
         if x == "a" || x == "e" || x == "i" || x == "o" || x == "u"
            x.capitalize!
          end
      end
    end
    x
  end

  result.join  
end

Answer 2

问题是你的问题。当 x 不是返回nil的元音时。

只需更改此行

if x == "a" || x == "e" || x == "i" || x == "o" || x == "u"
    x.capitalize!
end

有了这个

x = %w{a e i o u}.include?(x) ? x.capitalize : x

Array.map {| x |更改值}是从数组中删除它，为什么？

2 个答案: