In the previous entry we have seen how to read a FASTA file and display a simple output. The ability of reading such files in Bioinformatics is extremely relevant, so from now on most of our scripts that deal with sequences will use this feature. In the repository there is a link to the fasta.py which contains the code below 

class Fasta:
    def __init__(self, name, sequence):
        self.name = name
        self.sequence = sequence

def read_fasta(file):
    items = []
    index = 0
    for line in file:
        if line.startswith(">"):
           if index >= 1:
               items.append(aninstance)
           index+=1
           name = line[:-1]
           seq = ''
           aninstance = Fasta(name, seq)
        else:
           seq += line[:-1]
           aninstance = Fasta(name, seq)

    items.append(aninstance)
    return items

We are going to reuse this code several times, and now we only need to import by using

import fasta

and we are done. This will make everything easier. Please, be aware in the following posts the use of this simple module and download it from the repository if needed.