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  • rubygems/text.rb

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Gem::Text

A collection of text-wrangling methods

Public Instance Methods

format_text(text, wrap, indent=0) click to toggle source

Wraps text to wrap characters and optionally indents by indent characters

 
               # File rubygems/text.rb, line 12
def format_text(text, wrap, indent=0)
  result = []
  work = text.dup

  while work.length > wrap do
    if work =~ /^(.{0,#{wrap}})[ \n]/ then
      result << $1.rstrip
      work.slice!(0, $&.length)
    else
      result << work.slice!(0, wrap)
    end
  end

  result << work if work.length.nonzero?
  result.join("\n").gsub(/^/, " " * indent)
end
levenshtein_distance(str1, str2) click to toggle source

This code is based directly on the Text gem implementation Returns a value representing the “cost” of transforming str1 into str2

 
               # File rubygems/text.rb, line 31
def levenshtein_distance str1, str2
  s = str1
  t = str2
  n = s.length
  m = t.length
  max = n/2

  return m if (0 == n)
  return n if (0 == m)
  return n if (n - m).abs > max

  d = (0..m).to_a
  x = nil

  n.times do |i|
    e = i+1

    m.times do |j|
      cost = (s[i] == t[j]) ? 0 : 1
      x = [
           d[j+1] + 1, # insertion
           e + 1,      # deletion
           d[j] + cost # substitution
          ].min
      d[j] = e
      e = x
    end

    d[m] = x
  end

  return x
end

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