rubynarray

Replacing values in a byte type NArray in Ruby

I am looking for a way to replace all occurrences of 'A' with 1, 'T' with 2, 'C' with 8, and 'G' with 16 in a byte array. How can this be done?

Solution 
  • require "narray"

class NArray
  def cast(type)
    a = NArray.new(type,*self.shape)
    a[] = self
    a
  end
end

conv = NArray.int(256)
atcg = NArray.to_na('ATCG', NArray::BYTE).cast(NArray::LINT)
conv[atcg] = [1,2,8,16]

seq_str = 'ABCDAGDE'
seq_ary = NArray.to_na(seq_str, NArray::BYTE).cast(NArray::LINT)

p conv[seq_ary]
#=> NArray.int(8):
#   [ 1, 0, 8, 0, 1, 16, 0, 0 ]