Method: Bio::Sequence::NA#at_skew

Defined in:
lib/bio/sequence/na.rb

#at_skew ⇒ Object

Calculate the ratio of (A - T) / (A + T) bases. U is regarded as T.

s = Bio::Sequence::NA.new('atgttgttgttc')
puts s.at_skew                          #=> -0.75
Returns

Float



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# File 'lib/bio/sequence/na.rb', line 347

def at_skew
  count = self.composition
  a = count['a']
  t = count['t'] + count['u']
  return 0.0 if a + t == 0
  return (a - t).quo(a + t)
end