This sounded like a cute, simple task. https://www.youtube.com/watch?v=zp4BMR88260 . Avoiding regex to showoff ruby expressivity

digi_7_segment_word.rb

# frozen_string_literal: true
require 'set'

BAD_LETTERS = 'gkmqvwxz'
WORD_LIST_PATH = '/my_path/words_alpha.txt' # Found at https://github.com/dwyl/english-words/blob/master/words_alpha.txt

BAD_LETTERS_SET = BAD_LETTERS.split.to_set
WORD_LIST = File.new(WORD_LIST_PATH)

def word_check(word)
  word.each_char.none? { |char| BAD_LETTERS.include?(char) }
end

longest_word = ''
WORD_LIST.each_line do |word|
  next if longest_word.size >= word.size
  longest_word = word if word_check(word)
end

p "There is no word longer than '#{longest_word.chomp}' displayable on a 7 segment display"