Module: JLPT::Kanji

Defined in:
lib/jlpt/core/kanji.rb

Overview

Dedicated Kanji Character Analyzer and Extractor.

Identifies Kanji characters in Japanese text, maps them to JLPT levels (N5-N1), calculates kanji density, and extracts unique kanji filtered by level.

Constant Summary collapse

KANJI_REGEX = 
/[\u4E00-\u9FFF]/.freeze

Class Method Summary collapse

Class Method Details

.breakdown(text) ⇒ Hash{Symbol => Array<String>}

Detailed breakdown of Kanji by JLPT level

Parameters:

  • text (String) —

    Japanese text

Returns:

  • (Hash{Symbol => Array<String>}) —

    breakdown hash mapping levels to kanji arrays



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# File 'lib/jlpt/core/kanji.rb', line 44

def breakdown(text)
  res = { n5: [], n4: [], n3: [], n2: [], n1: [], out_of_jlpt: [] }
  extract(text).each do |k|
    lvl = Dictionary.kanji_level(k)
    res.key?(lvl) ? res[lvl] << k : res[:out_of_jlpt] << k
  end
  res
end

.density(text) ⇒ Float

Calculate Kanji density ratio (Kanji characters / Total characters)

Parameters:

  • text (String) —

    Japanese text

Returns:

  • (Float) —

    density ratio between 0.0 and 1.0



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# File 'lib/jlpt/core/kanji.rb', line 32

def density(text)
  cleaned = Preprocessor.clean(text)
  return 0.0 if cleaned.empty?

  kanji_count = cleaned.scan(KANJI_REGEX).length
  (kanji_count.to_f / cleaned.length).round(4)
end

.extract(text, level: nil) ⇒ Array<String>

Extract all Kanji characters from text

Parameters:

  • text (String) —

    Japanese text

  • level (Symbol, String, nil) (defaults to: nil) —

    optional JLPT level filter (:n5, :n4, :n3, :n2, :n1)

Returns:

  • (Array<String>) —

    array of unique Kanji characters



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# File 'lib/jlpt/core/kanji.rb', line 18

def extract(text, level: nil)
  return [] if text.nil? || text.to_s.strip.empty?

  kanjis = Preprocessor.clean(text).scan(KANJI_REGEX).uniq
  return kanjis if level.nil?

  target_level = level.to_s.downcase.to_sym
  kanjis.select { |k| Dictionary.kanji_level(k) == target_level }
end