Cute codecademy challenge

dna.py

sample = ['GTA','GGG','CAC']

def read_dna(dna_file):
  dna_data = ''
  with open(dna_file, 'r') as f:
    for line in f:
      dna_data += line
  return dna_data


def dna_codons(dna):
  codons = []
  for i in range(0, len(dna), 3):
    if i + 3 >= len(dna):
      break
    codons.append(dna[i] + dna[i+2] + dna[i+3])
  return codons  


def match_dna(dna):
  matches = 0
  for codon in dna:
    if codon in sample:
      matches += 1
  return matches


def is_criminal(dna_sample):
  dna_data = read_dna(dna_sample)
  codons = dna_codons(dna_data)
  num_matches = match_dna(codons)
  if num_matches >= 3:
    print('Matches: {}'.format(num_matches) + '\n' + 'Suspect: Continue investigation'.format(num_matches))
  else:
    print('Matches: {}'.format(num_matches) + '\n' + 'Suspect: Set free')
  

is_criminal("suspect1.txt")
is_criminal("suspect2.txt")
is_criminal("suspect3.txt")

suspect1.txt

ATCGAAAGCACAATCATGCATCGTGCCAGTGTGTTCGTGTCATCTAGGACGGGGCCATAGGATATATAATTCAATTAAGAATACCTTATACTACTGTCCCCTGTGGTTCGAAGGGGAACTATTTCGTGGGGCGAGCCCACACCGTCTCTTCTGCGGAAGACTTAACACGTTAGGGAGGTGGAATAGTTTCGAACGATGGTTATTAATCGTGATAACGGAACGCTGTCTGGAGGATGAGTCTGACGGTGTGTGACTCGATCAGTCACTCGCTATTCGAACTGCGCGAAAGATCCCAGCGCT

suspect2.txt

TCGCATAAGTACAGTAGATCCTCCCCGCGCATCCTATTTATTAAGTTAATTCTACAGCAATACGATCATATGCGGATCCGCAGTGGCCGGTAGACACACCATGCACTTGATTCCGAGGCCTGTCCCGATATATGAACCCAAACTAGAGCGAGGCTGTTGACGTTTGGAGTTGAAAAAATCTATTATACCAATCGGCTTCAACGTGCTCCACGGCAGGCGCCTGACGAGAGGCCCACACCGAGGAAGTAGACTGTTGCACGTTGAGGATAGCGCTAGCTAACAAAGACGCCTGCTACAACA

suspect3.txt

TCGCATAAGTACAGTAGATCCTCCCCGCGCATCCTATTTATTAAGTTAATTCTACAGCAATACGATCATATGCGGATCCGCAGTGGCCGGTAGACACACCATGCACTTGATTCCGAGGCCTGTCCCGATATATGAACCCAAACTAGAGCGAGGCTGTTGACGTTTGGAGTTGAAAAAATCTATTATACCAATCGGCTTCAACGTGCTCCACGGCAGGCGCCTGACGAGAGGCCCACACCGAGGAAGTAGACTGTTGCACGTTGAGGATAGCGCTAGCTAACAAAGACGCCTGCTACAACA