pset6 DNA - range() not working as expected

Question

DNA was a breeze until I got to the part where I have to check the dna sequences for patterns. Regardless of wich file I pass to the program it always detects only 1 repetition for every pattern.

Exemple of how I made my detection functions.

def agatc(s):
    maxrep = 0
    temp = 0
    for i in range(0, len(s) - 4, 1):
        if s[i] == "A" and s[i + 1] == "G" and s[i + 2] == "A" and s[i + 3] == "T" and s[i + 4] == "C":
            temp += 1
            print(i)
            i += 3
        else:
            if temp > maxrep:
                maxrep = temp
            temp = 0
    return maxrep

I though the problem might be in adding 3 to the i variable, so I added print(i) to see what was happening. I got the following:

45
1938
2049
2195
2952
2957
2962
2967
2972
2977
2982
2987
2992
2997
3002
3007
3012
3017
3022
3689
4754

Answer 1

When the "sequence" test (AGATC) is true, what is s[i + 3]? It is T. Therefore on the next iteration of the i loop, s[i] is T and temp will be reset.

Answer 2

Did you look at the longest_match() function provided in the code template? It is designed for this task.