Added doctest to hash_map.py

data_structures/hashing/hash_map.py

@@ -54,6 +54,26 @@ def _get_next_ind(self, ind: int) -> int:
         Get next index.
 
         Implements linear open addressing.
+
+        Example 1:
+        >>> hm = HashMap(5)
+        >>> hm._get_next_ind(3)
+        4
+
+        Example 2:
+        >>> hm = HashMap(5)
+        >>> hm._get_next_ind(5)
+        1
+
+        Example 3:
+        >>> hm = HashMap(5)
+        >>> hm._get_next_ind(6)
+        2
+
+        Example 4:
+        >>> hm = HashMap(5)
+        >>> hm._get_next_ind(9)
+        0
         """
         return (ind + 1) % len(self._buckets)
 
@@ -82,6 +102,16 @@ def _is_full(self) -> bool:
         Return true if we have reached safe capacity.
 
         So we need to increase the number of buckets to avoid collisions.
+
+        >>> hm = HashMap(2)
+        >>> hm._add_item(1,10)
+        >>> hm._add_item(2,20)
+        >>> hm._is_full()
+        True
+
+        >>> hm = HashMap(2)
+        >>> hm._is_full()
+        False
         """
         limit = len(self._buckets) * self._capacity_factor
         return len(self) >= int(limit)
@@ -114,17 +144,107 @@ def _iterate_buckets(self, key: KEY) -> Iterator[int]:
             ind = self._get_next_ind(ind)
 
     def _add_item(self, key: KEY, val: VAL) -> None:
+        """
+        1. Trying to add 3 elements when size is 5
+        >>> hm = HashMap(5)
+        >>> hm._add_item(1,10)
+        >>> hm._add_item(2,20)
+        >>> hm._add_item(3,30)
+        >>> hm
+        HashMap(1: 10 ,2: 20 ,3: 30)
+
+        2. Trying to add 3 elements when size is 5
+        >>> hm = HashMap(5)
+        >>> hm._add_item(-5,10)
+        >>> hm._add_item(6,30)
+        >>> hm._add_item(-7,20)
+        >>> hm
+        HashMap(-5: 10 ,6: 30 ,-7: 20)
+
+        3. Trying to add 3 elements when size is 1
+        >>> hm = HashMap(1)
+        >>> hm._add_item(10,13.2)
+        >>> hm._add_item(6,5.26)
+        >>> hm._add_item(7,5.155)
+        >>> hm
+        HashMap(10: 13.2)
+
+        4. Trying to add element with key in floating value
+        >>> hm = HashMap(5)
+        >>> hm._add_item(1.5,10)
+        >>> hm
+        HashMap(1.5: 10)
+
+        5. Trying to add item with same key
+        >>> hm = HashMap(5)
+        >>> hm._add_item(1,10)
+        >>> hm._add_item(1,20)
+        >>> hm
+        HashMap(1: 20)
+        """
         for ind in self._iterate_buckets(key):
             if self._try_set(ind, key, val):
                 break
 
     def __setitem__(self, key: KEY, val: VAL) -> None:
+        """
+        1. Changing value of item whose key is present
+        >>> hm = HashMap(5)
+        >>> hm._add_item(1,10)
+        >>> hm.__setitem__(1,20)
+        >>> hm
+        HashMap(1: 20)
+
+        2. Changing value of item whose key is not present
+        >>> hm = HashMap(5)
+        >>> hm._add_item(1,10)
+        >>> hm.__setitem__(0,20)
+        >>> hm
+        HashMap(0: 20 ,1: 10)
+
+        3. Changing value of same item multiple times
+        >>> hm = HashMap(5)
+        >>> hm._add_item(1,10)
+        >>> hm.__setitem__(1,20)
+        >>> hm.__setitem__(1,30)
+        >>> hm
+        HashMap(1: 30)
+        """
         if self._is_full():
             self._size_up()
 
         self._add_item(key, val)
 
     def __delitem__(self, key: KEY) -> None:
+        """
+        Example 1.
+        >>> hm = HashMap(5)
+        >>> hm._add_item(1,10)
+        >>> hm._add_item(2,20)
+        >>> hm._add_item(3,30)
+        >>> hm.__delitem__(3)
+        >>> hm
+        HashMap(1: 10 ,2: 20)
+
+        Example 2.
+        >>> hm = HashMap(5)
+        >>> hm._add_item(-5,10)
+        >>> hm._add_item(6,30)
+        >>> hm._add_item(-7,20)
+        >>> hm.__delitem__(-5)
+        >>> hm
+        HashMap(6: 30 ,-7: 20)
+
+        Example 3: Trying to remove non-existing item
+        >>> hm = HashMap(5)
+        >>> hm._add_item(1,10)
+        >>> hm._add_item(2,20)
+        >>> hm._add_item(3,30)
+        >>> hm.__delitem__(4)
+        Traceback (most recent call last):
+        ...
+        KeyError: 4
+        """
         for ind in self._iterate_buckets(key):
             item = self._buckets[ind]
             if item is None:
@@ -160,3 +280,9 @@ def __repr__(self) -> str:
             f"{item.key}: {item.val}" for item in self._buckets if item
         )
         return f"HashMap({val_string})"
+
+if __name__ == "__main__":
+
+    import doctest
+
+    doctest.testmod()