Find the Vowels

It’s a Saturday night - what else would a newbie coding student be doing other than working on problems in Codewars?

Codewars is my preferred practice resource for a few reasons – chiefly because once a kata is solved, I get to see other, often more elegant ways to solve the problem. Working through various kata has introduced me to a number a cool methods and bits of code – reduce and inject are recent favorites.

Here are the instructions for a kata I just solved:

We want to know the index of the vowels in a given word, for example, there are two vowels in the word super (the second and fourth letters).

So given a string “super”, we should return a list of [2, 4].

Some examples: Mmmm => [] Super => [2,4] Apple => [1,5] YoMama -> [1,2,4,6] NOTE: Vowels in this context refers to English Language Vowels - a e i o u y

NOTE: this is indexed from [1..n] (not zero indexed!)

My first attempt was a long, messy piece of code that yielded an even longer error message.

def vowel_indices(word)
  answer = [ ]
  word_as_array = word.split(//)
  word_as_array.map do |letter|
  answer << word_as_array[letter]
  end
  answer
end

I had a bit of a think (and a few fruitless searches for a simple method to identify vowels in a string) and went back to a blog post I recently read on Regexp. Regular expressions still feel like Greek - but it was worth a go. After refining, and refactoring this was my final solution:

def vowel_indices(word)
  word.chars.map.with_index(1) {|letter, index| index if /[aeiouy]/i =~ letter }.compact
end

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