How to compare user input with values in a hash

Question

I'm trying to compare user input to values in my hash.

For example, if I ran "e".scrabble() in IRB, it would return the value for "e" in my hash.

I figured out how to identify if it's in my hash and if it's equal to one of the keys in the hash.

class String
  define_method(:scrabble) do
    value_for_letters = {
      "A"=> 9,"B" => 2,"C" => 2,"D" => 4,"E" => 12,"F" => 2,
      "G" => 3, "H" => 2, "I" => 9,"J" => 1, "K" => 1,    
      "L" => 4,"M" => 2,"N" => 6,"O" => 8,"P" => 2,"Q" => 1,
      "R" => 6,"S" => 4,"T" => 6,"U" => 4,"V" => 2,"W" => 2,
      "X" => 1,"Y" => 2,"Z" => 1
    }

    value_for_letters.keys().==(self.capitalize())
    "true"
  end
end

I simply reformatted your code slightly to conform with the Ruby convention of indenting two spaces. There are two things I found a bit odd with your code: that you chose to use define_method rather than simply def scrabble... and that you invoked the method String#== in the formal way (.==(...)), rather than using the "syntactic sugar" keys() == self.capitalize (the extra parens are not necessary, btw). I suspect that's what you are being taught in your early days of learning Ruby, which is a very good thing! You will learn the conventional methods soon enough. — Cary Swoveland
– Cary Swoveland, Commented Apr 13, 2017 at 15:35

spickermann · Accepted Answer · 2017-04-13 15:36:48Z

2

class String
  LETTER_VALUE_MATCHING = { 
    'A' => 9, 'B' => 2, 'C' => 2, 'D' => 4, 'E' => 12, 
    'F' => 2, 'G' => 3, 'H' => 2, 'I' => 9, 'J' => 1, 
    'K' => 1, 'L' => 4, 'M' => 2, 'N' => 6, 'O' => 8, 
    'P' => 2, 'Q' => 1, 'R' => 6, 'S' => 4, 'T' => 6, 
    'U' => 4, 'V' => 2, 'W' => 2, 'X' => 1, 'Y' => 2, 
    'Z' => 1
  }

  def scrabble
    LETTER_VALUE_MATCHING[self.capitalize]
  end
end

'a'.scrabble
# => 9
'-'.scrabble
# => nil

edited Apr 13, 2017 at 15:36

answered Apr 13, 2017 at 15:25

spickermann

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4 Comments

Aleksei Matiushkin Over a year ago

self is redundant and an umlaut is not well recognizable, which made me “wtf?” for a while. Here is some more evident Cyrillic: “Щ” :)

Jordan Running Over a year ago

@mudasobwa "💩".scrabble

Aleksei Matiushkin Over a year ago

@Jordan even better, indeed.

Aleksei Matiushkin Over a year ago

Bonus track: count a word value "abc".split('').map(&:scrabble).reduce(:+).

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