added some set code

Author: Catislin

source/Set.py

@@ -0,0 +1,67 @@
+from linkedlist import LinkedList
+
+class Set(object):
+    def __init__(self, elements=None):
+        self.size = 0
+        if elements:
+            self.buckets = [LinkedList() for i in range(len(elements))]
+            for element in elements:
+                self.add(element)
+        else:
+            self.buckets = [LinkedList() for i in range(init_size)]
+
+    def __str__(self):
+        pass
+
+    def _bucket_index(self, item):
+        """Hashes the item and returns the index of the bucket it is hashed to"""
+        return hash(item) % len(self.buckets)
+
+    def _load_factor(self):
+        """ Returns the ratio of the number of items to the number of buckets """
+        return self.size / len(self.buckets)
+
+    def get_items(self):
+        return_list = []
+        for bucket in self.buckets:
+            for item in bucket:
+                return_list.append(item)
+        return return_list
+
+
+    def add(self, item):
+        """Adds the specified item only if it is not only present in the Set"""
+        if not self.contains(item):
+            bucket_index = self._bucket_index(item)
+            self.buckets[bucket_index].append(item)
+            self.size += 1
+
+    def get(self, item):
+        """Returns the specified items, returns None if not found """
+        bucket_index = self._bucket_index(item)
+        return self.buckets[bucket_index].find(lambda value: value == item)
+
+    def contains(self, item):
+        bucket_index = self._bucket_index(item)
+        return self.buckets[bucket_index].find(lambda value: value == item) is not None
+
+    def is_subset(self, other):
+        for bucket in self.buckets:
+            for item in bucket.iterate():
+                if not other.contains(item):
+                    return False
+        return True
+
+    def union(self, other):
+        new_set = Set()
+
+
+
+
+
+if __name__ == '__main__':
+    A = Set(['a', 'b'])
+    B = Set(['a', 'b', 'c'])
+    A.add('b')
+    print(A.is_subset(B))
+    print(B.is_subset(A))

source/linkedlist.py

@@ -220,6 +220,13 @@ def delete(self, item):
             # Otherwise raise an error to tell the user that delete has failed
             raise ValueError('Item not found: {}'.format(item))
 
+    def iterate(self):
+        """Iterate from the head of the list"""
+        current = self.head
+        while current:
+            yield current.data
+            current = current.next
+
 
 def test_linked_list():
     ll = LinkedList()

source/set_test.py

@@ -0,0 +1,4 @@
+import unittest
+
+class SetTest(unittest.TestCase)
+    def test_contains(self):