week 1 day 4 vowels homework

vowels.rb

def is_a_vowel1(letter)
  if letter == "a"
    return true
  elsif letter == "e"
    return true
  elsif letter == "i"
    return true
  elsif letter == "o"
    return true
  elsif letter == "u"
    return true
  else
    return false
  end
end

def is_a_vowel2(letter)
  case letter
  when "a"
    true
  when "e"
    true
  when "i"
    true
  when "o"
    true
  when "u"
    true
  else
    false
  end
end
p is_a_vowel2("e")
def is_a_vowel3(letter)
  if letter == "a" || letter == "e" || letter == "i" || letter == "o" || letter == "u"
    return true
  else 
    return false 
  end
end

def is_a_vowel4(letter)
  return letter == "a" || letter == "e" || letter == "i" || letter == "o" || letter == "u"
end

def is_a_vowel5(letter)
  "aeiou".include?(letter)
end

def first_vowel(string)
  string.split("").each do |x|
    return x if is_a_vowel4(x)
  end
end
def first_vowel_index(string)
  string.split("").each do |x|
    if is_a_vowel4(x)
      return string.index(x)
    end
  end
end

puts first_vowel_index("This is a cool string")