Question

match_enzymes: (str, List[str], List[str]) -> List[list]

The return type is a list of two-item [str, List[int]] lists

The first parameter represents a strand of DNA. The last two parameters are parallel lists: the second parameter is a list of restriction enzyme names, and the third is the corresponding list of recognition sequences. (For example, if the first item in the second parameter is 'BamHI', then the first item in the third parameter would be 'GGATCC', since the restriction enzyme named BamHI has the recognition sequence GGATCC — you can refer to the table of restriction enzymes to see more examples of restriction enzymes and their recognition sequences.) Return a list of two-item lists where the first item of each two-item list is the name of a restriction enzyme and the second item is the list of indices (in the DNA strand) of the restriction sites that the enzyme cuts.

The indices in the sublist that is returned are the indices of the start of each occurrence of the corresponding recognition sequence in the DNA strand.

Hint: how can you use function restriction_sites?

From the FAQ:

Question: In match_enzymes, should an enzyme be included in the returned list if its recognition sequence does not appear in the strand?

Answer: Yes it should, but the list of indices associated with the enzyme should be an empty list. The length of the list returned by match_enzymes must be the same as the length of the two parallel lists (enzyme names, corresponding recognition sequences).

Answer 1

def match_enzymes(DNA,namesList,sequenceList):
    result=[]
    for j in range(len(namesList)):
        sequence=sequenceList[j]
        i = 0
        indices = []
        while i != -1:
            i = DNA.find(sequence, i)
            if i != -1:
                indices.append(i)
                i = i + len(sequence)
        result.append([namesList[j],indices])
    return result