Python-2/strings/dna.py at master · https-github-com-nzysoft/Python-2 · GitHub

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import re

def dna(dna: str) -> str:

"""

https://en.wikipedia.org/wiki/DNA

Returns the second side of a DNA strand

>>> dna("GCTA")

'CGAT'

>>> dna("ATGC")

'TACG'

>>> dna("CTGA")

'GACT'

>>> dna("GFGG")

Traceback (most recent call last):

...

ValueError: Invalid Strand

"""

if len(re.findall("[ATCG]", dna)) != len(dna):

raise ValueError("Invalid Strand")

return dna.translate(dna.maketrans("ATCG", "TAGC"))

if __name__ == "__main__":

import doctest

doctest.testmod()

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