Rewrote the HashMap implementation (barely understand in the whole)

Author: codingEzio

chap05_sets_maps/hashmap.py

@@ -0,0 +1,64 @@
+from map_hashset import HashSet
+
+
+class HashMap:
+    """
+    It has many faces(names), including map, dictionary, and hash tables.
+
+    Status for this class:
+    - barely understood, since I haven't even finish documented the `HashSet`.
+    - start to work through this class after you finish the `HashSet`!
+        - or you could read and code other implementations :)
+    """
+
+    class __KVPair:
+        def __init__(self, key, value):
+            self.key = key
+            self.value = value
+
+        def __eq__(self, other):
+            if type(self) != type(other):
+                return False
+
+            return self.key == other.key
+
+        def get_key(self):
+            return self.key
+
+        def get_value(self):
+            return self.value
+
+        def __hash__(self):
+            return hash(self.key)
+
+    def __init__(self):
+        self.hashset = HashSet()
+
+    def __len__(self):
+        return len(self.hashset)
+
+    def __contains__(self, item):
+        return HashSet.__KVPair(item, None) in self.hashset
+
+    def __setitem__(self, key, value):
+        self.hashset.add(HashMap.__KVPair(key, value))
+
+    def __getitem__(self, key):
+        if HashMap.__KVPair(key, None) in self.hashset:
+            value = self.hashset[HashMap.__KVPair(key, None)].get_value()
+
+            return value
+
+        raise KeyError(f"Key {str(key)} not in HashMap")
+
+    def __iter__(self):
+        for item in self.hashset:
+            yield item.get_key()
+
+
+def main():
+    pass
+
+
+if "__main__" == __name__:
+    main()

chap05_sets_maps/map_hashmap.py

@@ -179,6 +179,24 @@ def __contains__(self, item):
 
         return False
 
+    def __getitem__(self, item):
+        """
+        O(?)
+
+        This method is specifically written for the external `HashMap` to use.
+        The `HashSet` class itself does NOT require this method to work.
+        """
+        idx = hash(item) % len(self.items)
+
+        while self.items[idx] is not None:
+            if self.items[idx] == item:
+                return self.items[idx]
+
+            # TODO document this
+            idx = (idx + 1) % len(self.items)
+
+        return None
+
     def __iter__(self):
         """
         O(?)