1 files changed, 23 insertions, 0 deletions
diff --git a/lib/zipf/SparseVector.rb b/lib/zipf/SparseVector.rb
index 3096412..33bb396 100644
--- a/lib/zipf/SparseVector.rb
+++ b/lib/zipf/SparseVector.rb
@@ -1,3 +1,6 @@
+require 'json'
+
+
 class SparseVector < Hash
 
   def initialize arg=nil
@@ -18,6 +21,12 @@ class SparseVector < Hash
     return v
   end
 
+  def to_h
+    h = {}
+    self.each_pair { |k,v| h[k] = v }
+    return h
+  end
+
   def from_h h
     h.each_pair { |k,v| self[k] = v }
   end
@@ -53,6 +62,20 @@ class SparseVector < Hash
     }
   end
 
+  def to_json
+    JSON.dump self.to_h
+  end
+
+  def from_json s
+    from_h JSON.load(s)
+  end
+
+  def self.from_json s
+    v = SparseVector.new
+    v.from_json s
+    return v
+  end
+
   def self.from_kv s
     v = SparseVector.new
     v.from_kv s