Exercise: DNA sequencing

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• Create a file called dna_sequencing.py
• A, C, T, G are called bases or nucleotides
• Accept a sequence on the command line like this: python dna_sequencing.py ACCGXXCXXGTTACTGGGCXTTGTXX
• Given a sequence such as the one above (some nucleotides mixed up with other elements represented by an X)
• First return the sequences containing only ACTG. The above string can will be changed to ['ACCG', 'C', 'GTTACTGGGC', 'TTGT'].
• Then sort them by lenght. Expected result: ['GTTACTGGGC', 'ACCG', 'TTGT', 'C']

• Create a file called extended_dna_sequencing.py
• In this case the original string contains more than on type of foreign elements: e.g. 'ACCGXXTXXYYGTTQRACQQTGGGCXTTGTXX'.
• Expected output: ['TGGGC', 'ACCG', 'TTGT', 'GTT', 'AC', 'T']
• Ask for a sequence on the Standard Input (STDIN) like this:

python extended_dna_sequencing.py
Please type in a sequence: