added feature to sort multiple datafields

1 files changed, 37 insertions, 0 deletions

diff --git a/hash.rb b/hash.rb
new file mode 100644
index 0000000..dcd1724
--- /dev/null
+++ b/hash.rb
@@ -0,0 +1,37 @@
+class Hash
+	def compare_by_values(other, fieldarray)
+		return  0 if fieldarray.size == 0
+		return -1 if  self[fieldarray[0]].nil?
+		return  1 if other[fieldarray[0]].nil?
+
+		if self[fieldarray[0]] == other[fieldarray[0]]
+			if fieldarray.size == 1
+				return 0
+			else
+				return self.compare_by_values(other, fieldarray[1,fieldarray.size-1])
+			end
+		else
+			self[fieldarray[0]] <=> other[fieldarray[0]]
+		end
+	end
+end
+
+if __FILE__ == $0
+require "test/unit"
+  class Hash_test < Test::Unit::TestCase
+    def test_compare_by_values
+			a = {1 =>1, 2=>2, 3=>3}
+			b = {1 =>1, 2=>2, 3=>2}
+			c = {1 =>1, 2=>3, 3=>3}
+			d = {1 =>1, 2=>3}
+
+      assert_equal( 0,a.compare_by_values(a,[1,2,3]))
+      assert_equal( 1,a.compare_by_values(b,[1,2,3]))
+      assert_equal(-1,a.compare_by_values(c,[1,2,3]))
+      assert_equal( 1,c.compare_by_values(d,[1,2,3]))
+      assert_equal(-1,d.compare_by_values(c,[1,2,3]))
+      assert_equal( 0,d.compare_by_values(c,[]))
+    end
+  end 
+end
+