해시 테이블 구현

Python code

class HashTable:
    def __init__(self, size=16):
        self._size = size
        self._buckets: list[list] = [[] for _ in range(size)]
        self._count = 0

    def _hash(self, key) -> int:
        return hash(key) % self._size

    def __setitem__(self, key, value):
        bucket = self._buckets[self._hash(key)]
        for i, (k, v) in enumerate(bucket):
            if k == key:
                bucket[i] = (key, value)
                return
        bucket.append((key, value))
        self._count += 1

    def __getitem__(self, key):
        bucket = self._buckets[self._hash(key)]
        for k, v in bucket:
            if k == key:
                return v
        raise KeyError(key)

    def __contains__(self, key):
        try:
            self[key]
            return True
        except KeyError:
            return False

    def __len__(self):
        return self._count

ht = HashTable()
ht["name"] = "Alice"
ht["age"] = 30
ht["city"] = "서울"
print(ht["name"])       # Alice
print("age" in ht)      # True
print(len(ht))          # 3