Question

this is for bioinformatics. Write a Python script that prints the total number of A's in sequences
given in FASTA format in a file called dna.fasta. The input may contain
more than two sequences of any length.

2. Write a Python program that prints length of the longest
sequence in the file dna.txt given in FASTA format.

For example if the file contains

>human
ACCGT
>mouse
AGTTATATA
>cat
AGT
>dog
GTGTATA

then the output should be
9
Write a Python script that takes from the user an input DNA
sequence and prints the percentage of A's, C's, G's, and T's.

Answer 1

OK. How far did you get with the code?

Also, a great reference for Python informatics programming is this:
http://www.pythonlearn.com/book.php

It is free and there are videos to go with the book.