Question

RUBY

Write a DNA class that gets initialized with a string of nucleotide characters. An instance of DNA responds to the to_s, length, hamming_distance, contains, positions, and frequencies messages. Where a and b are DNA instances of the same length, the message send a.hamming_distance(b) returns the Hamming distance between a and b. a.contains(b) returns true if b appears as a substring in a, and returns false otherwise. a.positions(n) returns an array of the (zero-based) positions in which the nucleotide n occurs in increasing order. Frequencies returns a hash that maps each of the four nucleotides to the number of times it occurs in the DNA instance.

output:

>> dna1 = DNA.new('ATTGCC') => ATTGCC
>> dna1.length
=> 6

>> puts dna1
ATTGCC
>> dna1.contains('TGC')
true
>> dna1.contains(DNA.new('AT'))
true
>> dna1.contains('GG')
false
>> dna1.positions('T')
[1, 2]
>> dna2 = DNA.new('GTTGAC')
=> GTTGAC
>> dna1.hamming_distance(dna2)
=> 2
>> dna1.hamming_distance(dna1)
=> 0
>> dna1.hamming_distance(DNA.new('AT')) ArgumentError: dnas of different lengths

from ass2.rb:17:in `hamming_distance' from (irb):8
from C:/Ruby22/bin/irb:11:in '<main>'

>> dna1.frequencies
{"A"=>1, "T"=>2, "G"=>1, "C"=>2}

Answer 1

Copiable code:

class DNA

def initialize(string_dna)

@str_dna=string_dna

end

# method for print

def printdna()

puts @str_dna

end

# method for return

def getstring()

return @str_dna

end

# method for returning the length

def length

puts @str_dna.length

return @str_dna.length

end

  

#method for computing distance

def hamming_distance(dna2)

#If length not matched, return an error message

if @str_dna.length!=dna2.length

puts "ArgumentError: DNAs of different lengths"

#Compute distance

else

$ival = 0

$numval = dna2.length

$cnt_lo=0

begin

if @str_dna[$ival].chr!= dna2.getstring()[$ival].chr

$cnt_lo+=1

end

$ival +=1

end

while $ival < $numval

puts $cnt_lo

return $cnt_lo

end

end

end

end