Counting DNA Nucleotides

25 Oct 2023 in Study / Rosalind on Rosalind problem

A problem from rosalind “Bioinformatics Stronghold” category, Dictionary

• A problem from rosalind “Bioinformatics Stronghold” category
  Rosalind Problem Link

• Description
  • Given DNA sequence, we should calculate the numbers of each base
• Input example : AGGCCTTAGGCAGT
• Output example : 3 3 5 3 (A C G T)

Biological Background

• DNA sequences consist of 4 bases (A, C, G, T)

My Solution

d = {}

seqs = input()

for i in range(len(seqs)):
    symbol = seqs[i]
    if symbol not in d:
        d[symbol] = 1
    else:
        d[symbol] += 1

d = sorted(d.items())

for k, v in d:
    print(v, end=' ')

• I use the dictionary for counting the numbers of each base
• sorted(d.items()) : sorting the dictionary based on the key
  • sorted(d.items(), reverse = True) : reverse sorting
  • sorted(d.items(), key = lambda x : x[1]) : sorting it based on the value
  • sorted(d.items(), key = lambda x : x[1], reverse = True) : reverse sorting