From 3ba96f05e59c0045443abff750fd05427d41349f Mon Sep 17 00:00:00 2001
From: Sedat Aybars Nazlica <saybarsnazlica@gmail.com>
Date: Mon, 13 Jun 2022 22:00:59 +0900
Subject: [PATCH 1/4] Add hamming distance

---
 strings/hamming_distance.py | 41 +++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 strings/hamming_distance.py

diff --git a/strings/hamming_distance.py b/strings/hamming_distance.py
new file mode 100644
index 000000000000..03b8beac3a90
--- /dev/null
+++ b/strings/hamming_distance.py
@@ -0,0 +1,41 @@
+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
+    """
+    assert len(string1) == len(string2)
+
+    count = 0
+
+    for i in range(len(string1)):
+        if string1[i] != string2[i]:
+            count += 1
+
+    return count
+
+
+if __name__ == "__main__":
+
+    def test_hamming_distance():
+        assert hamming_distance("", "") == 0
+        assert hamming_distance("python", "python") == 0
+        assert hamming_distance("karolin", "kathrin") == 3
+        assert hamming_distance("kathrin", "kerstin") == 4
+        assert hamming_distance("00000", "11111") == 5
+
+    test_hamming_distance()

From 196dc9373bbc87045f2a469260377ba913a5f6d2 Mon Sep 17 00:00:00 2001
From: Sedat Aybars Nazlica <saybarsnazlica@gmail.com>
Date: Mon, 13 Jun 2022 22:10:25 +0900
Subject: [PATCH 2/4] Fix doctest

---
 strings/hamming_distance.py | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/strings/hamming_distance.py b/strings/hamming_distance.py
index 03b8beac3a90..05878d5b4459 100644
--- a/strings/hamming_distance.py
+++ b/strings/hamming_distance.py
@@ -31,11 +31,6 @@ def hamming_distance(string1: str, string2: str) -> int:
 
 if __name__ == "__main__":
 
-    def test_hamming_distance():
-        assert hamming_distance("", "") == 0
-        assert hamming_distance("python", "python") == 0
-        assert hamming_distance("karolin", "kathrin") == 3
-        assert hamming_distance("kathrin", "kerstin") == 4
-        assert hamming_distance("00000", "11111") == 5
-
-    test_hamming_distance()
+    import doctest
+
+    doctest.testmod()

From 1771ae45cdec52e4ef0a815dca4f24cf69034f85 Mon Sep 17 00:00:00 2001
From: Sedat Aybars Nazlica <saybarsnazlica@gmail.com>
Date: Tue, 14 Jun 2022 21:27:50 +0900
Subject: [PATCH 3/4] Refactor

---
 strings/hamming_distance.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/strings/hamming_distance.py b/strings/hamming_distance.py
index 05878d5b4459..3d5f359452ed 100644
--- a/strings/hamming_distance.py
+++ b/strings/hamming_distance.py
@@ -22,8 +22,8 @@ def hamming_distance(string1: str, string2: str) -> int:
 
     count = 0
 
-    for i in range(len(string1)):
-        if string1[i] != string2[i]:
+    for char1, char2 in zip(string1, string2):
+        if char1 != char2:
             count += 1
 
     return count

From 668f07df43898aa1580b62b1df1ade12483e8408 Mon Sep 17 00:00:00 2001
From: Sedat Aybars Nazlica <saybarsnazlica@gmail.com>
Date: Mon, 4 Jul 2022 13:17:42 +0900
Subject: [PATCH 4/4] Raise ValueError when string lengths are different

---
 strings/hamming_distance.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/strings/hamming_distance.py b/strings/hamming_distance.py
index 3d5f359452ed..b8feaef06190 100644
--- a/strings/hamming_distance.py
+++ b/strings/hamming_distance.py
@@ -17,8 +17,11 @@ def hamming_distance(string1: str, string2: str) -> int:
     3
     >>> hamming_distance("00000", "11111")
     5
+    >>> hamming_distance("karolin", "kath")
+    ValueError: String lengths must match!
     """
-    assert len(string1) == len(string2)
+    if len(string1) != len(string2):
+        raise ValueError("String lengths must match!")
 
     count = 0