Python/strings/hamming_distance.py

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def hamming_distance(string1: str, string2: str) -> int:
"""Calculate the Hamming distance between two equal length strings
In information theory, the Hamming distance between two strings of equal
length is the number of positions at which the corresponding symbols are
different. https://en.wikipedia.org/wiki/Hamming_distance
Args:
string1 (str): Sequence 1
string2 (str): Sequence 2
Returns:
int: Hamming distance
>>> hamming_distance("python", "python")
0
>>> hamming_distance("karolin", "kathrin")
3
>>> hamming_distance("00000", "11111")
5
>>> hamming_distance("karolin", "kath")
Traceback (most recent call last):
...
ValueError: String lengths must match!
"""
if len(string1) != len(string2):
raise ValueError("String lengths must match!")
count = 0
for char1, char2 in zip(string1, string2):
if char1 != char2:
count += 1
return count
if __name__ == "__main__":
import doctest
doctest.testmod()