Hamming distance between two strings in Python

Question

I need to find the Hamming distance between two strings:

chaine1 = 6fb17381822a6ca9b02153d031d5d3da

chaine2 = a242eace2c57f7a16e8e872ed2f2287d

The XOR function didn't work, and my search on the web was not very successful.

I tried to modify something I found on the web, but there's some invalid syntax...:

assert len (chaine1) == len(chaine2)

return sum(chaine1 != chaine2 for chaine1, chaine2 in zip(chaine1, chaine2))


if __name__=="__main__":
chaine1 = hashlib.md5("chaine1".encode()).hexdigest()

chaine2 = hashlib.md5("chaine2".encode()).hexdigest()
print hamming_distance(chaine1, chaine2)

How could I proceed?

Answer 1

Following is a program calculating the Hamming distance using two different ways.

import hashlib

def hamming_distance(chaine1, chaine2):
    return sum(c1 != c2 for c1, c2 in zip(chaine1, chaine2))

def hamming_distance2(chaine1, chaine2):
    return len(list(filter(lambda x : ord(x[0])^ord(x[1]), zip(chaine1, chaine2))))

if __name__=="__main__":    
    chaine1 = hashlib.md5("chaine1".encode()).hexdigest()
    chaine2 = hashlib.md5("chaine2".encode()).hexdigest()
    
    #chaine1 = "6fb17381822a6ca9b02153d031d5d3da"
    #chaine2 = "a242eace2c57f7a16e8e872ed2f2287d"
    
    assert len(chaine1) == len(chaine2)
    
    print(hamming_distance(chaine1, chaine2))
    
    print(hamming_distance2(chaine1, chaine2))

The reason why you get Invalid syntax: ... is probably you don't have any indentations, which are required in Python.

Answer 2

from scipy.spatial import distance

DNA1 = list("GAGCCTACTAACGGGAT")
DNA2 = list("CATCGTAATGACGGCCT") 

d = round(distance.hamming(DNA1, DNA2) * len(DNA1))
print(d)  # 7