MIT 6.00 Assignments solution

ps3c.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from ps3b import subStringMatchExact


def constrainedMatchPair(firstMatch, SecondMatch, lenth):
    ans = ()
    for i in firstMatch:
        for j in SecondMatch:
            if i + 1 + lenth == j:
                ans += (i, )
    return ans


def subStringMatchOneSub(key, target):
    """search for all locations of key in target, with one substitution"""
    allAnswers = ()
    for miss in range(0, len(key)):
        # miss picks location for missing element
        # key1 and key2 are substrings to match
        key1 = key[:miss]
        key2 = key[miss + 1:]
        print('breaking key', key, 'into', key1, key2)
        # match1 and match2 are tuples of locations of start of matches
        # for each substring in target
        match1 = subStringMatchExact(target, key1)
        match2 = subStringMatchExact(target, key2)
        # when we get here, we have two tuples of start points
        # need to filter pairs to decide which are correct
        filtered = constrainedMatchPair(match1, match2, len(key1))
        allAnswers = allAnswers + filtered
        print('match1', match1)
        print('match2', match2)
        print('possible matches for', key1, key2, 'start at', filtered)
    return allAnswers

print(subStringMatchOneSub("ATGC", "ATGACATGCA"))