Question

python/idle

1. Write a program that counts the number of A’s in a DNA sequence. The input is one sequence in FASTA format in a file called ‘dna.txt’. For example, if the file contains: >human ACCGT then the output of the program should be 1. Your program should work for any sequence and not just the one in the example.

Answer 1

thanks for the question, here is the program in python.

Note:

    # update the filename in the below line
    filename='D:\\dna.txt'

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def main():
    # update the filename in the below line
    filename='D:\\dna.txt'

    countA=0
    with open(filename,'r') as infile:
        for line in infile.readlines():
            for letter in line.strip():
                countA+=1 if letter=='A' else 0
    print('A occurred {} times'.format(countA))
main()

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