Module: Analysis

Defined in:
lib/dekryptos/analysis.rb

Overview

Tools for analyzing suggested Kryptos solutions.

Instance Method Summary collapse

Instance Method Details

#anagram(text) ⇒ Object

Public: Provides all anagrams for a given word.

Parameter(s)

text - String: The text to anagram.

Return Value

Array<String>: A list of anagrams. rubocop: disable MethodLength, UnderscorePrefixedVariableName



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# File 'lib/dekryptos/analysis.rb', line 34

def anagram(text)
  head, tail = [], text.split('')
  stack = [[head, tail]]
  result = []

  while stack.size > 0
    head, tail = stack.pop
    if tail.size.zero?
      result << head
    else
      tail.each_with_index do |_, i|
        _tail = tail.dup
        curr  = _tail.delete_at(i)
        _head = head.dup
        _head << curr
        stack << [_head, _tail]
      end
    end
  end

  result.map! { |p| p.join('') }
  result.uniq!
  result
end

#anagram?(phrase_one, phrase_two) ⇒ Boolean

Public: Checks whether one word or phrase is an anagram of another.

Parameter(s)

phrase_one - String: A word or phrase. phrase_two - String: A word or phrase that may be an anagram of phrase_one.

Return Value

Boolean: True if one phrase is an anagram of the other, false otherwise.



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# File 'lib/dekryptos/analysis.rb', line 71

def anagram?(phrase_one, phrase_two)
  phrase_one.split('').sort == phrase_two.split('').sort
end

#factor(n) ⇒ Object

Public: Provides all factors of a given number.

Parameter(s)

n - Integer: The number to factor.

Return Value

Array<Integer>: A list of factors.



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# File 'lib/dekryptos/analysis.rb', line 17

def factor(n)
  factors = []
  (1..n).each do |x|
    factors << x if n % x == 0
  end

  factors
end

#frequency(text) ⇒ Object

Public: Performs frequency analysis on the provided text.

Parameter(s)

text - String: The text to analyze.

Return Value

Hash<String, Integer>: A hash representing the letter frequencies.



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# File 'lib/dekryptos/analysis.rb', line 84

def frequency(text)
  text  = text.downcase.gsub(/\s*/, '')
  chars = text.split('')
  freqs = Hash[('a'..'z').to_a.zip([0] * 26)]

  chars.each do |c|
    freqs[c] += 1
  end

  freqs
end

#ioc(text) ⇒ Object

Public: Calculates the index of coincidence for the given text (see en.wikipedia.org/wiki/ Index_of_coincidence).

Parameter(s)

text - String: The text to analyze.

Return Value

Float: The index of coincidence for the text.



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# File 'lib/dekryptos/analysis.rb', line 105

def ioc(text)
  c     = 26.0
  freqs = frequency(text)
  n     = text.length

  f = freqs.values.reduce(0) { |a, e| a + (e * (e - 1)) }
  f / ((n * (n - 1)) / c)
end

#vowels(text) ⇒ Object

Public: Calculates the percentage of text composed of vowels. (Y is not included as a vowel.)

Parameter(s)

text - String: The text to analyze.

Return Value

Float: The percentage comprising vowels.



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# File 'lib/dekryptos/analysis.rb', line 122

def vowels(text)
  vowels = %w(A E I O U)
  chars = text.upcase.split('')
  vowel_count = 0
  chars.each do |c|
    vowel_count += 1 if vowels.include? c
  end

  vowel_count.to_f / text.length
end