How do I remove the last vowel in a string in Ruby?

问题

How can I define the -last vowel- in a string?

For example, I have a word "classic"

I want to find that the last vowel of the word "classsic" is the letter "i", and delete that last vowel.

I'm thinking :

def vowel(str)
  result = ""
  new = str.split(" ")
  i = new.length - 1
  while i < new.length
    if new[i] == "aeiou"
      new[i].gsub(/aeiou/," ")
    elsif new[i] != "aeiou"
      i = -= 1
    end
  end
  return result
end

回答1:

r = /
    .*      # match zero or more of any character, greedily
    \K      # discard everything matched so far
    [aeiou] # match a vowel
    /x      # free-spacing regex definition mode

"wheelie".sub(r,'') #=> "wheeli"
"though".sub(r,'')  #=> "thogh"
"why".sub(r,'')     #=> "why" 

回答2:

Like @aetherus pointed out: reverse the string, remove the first vowel then reverse it back:

str = "classic"
=> "classic"
str.reverse.sub(/[aeiou]/, "").reverse
=> "classc"

回答3:

regex = /[aeiou](?=[^aeiou]*\z)/

• [aeiou] matches one vowel

• [^aeiou]* matches non-vowel characters 0 or more times

• \z matches to the end of the string

• (?=...) is positive forward looking and not including the match in the final result.

Here are a few examples:

"classic".sub(regex, '') #=> "classc"
  "hello".sub(regex, '') #=> "hell"
  "crypt".sub(regex, '') #=> "crypt

来源：https://stackoverflow.com/questions/39628583/how-do-i-remove-the-last-vowel-in-a-string-in-ruby