--- a/numerics/data.py	Mon Sep 29 16:19:35 2014 -0700
+++ b/numerics/data.py	Fri Oct 03 17:29:42 2014 -0700
@@ -4,10 +4,46 @@
 data models
 """
 
-__all__ = ['Dataset']
-string = (str, unicode)
+from collections import OrderedDict
+
+__all__ = ['Rows', 'Columns']
+
+
+class ColumnNumberException(Exception):
+    """
+    wrong number of columns: {given} given; {expected} expected
+    """
+    def __init__(self, given, expected):
+        self.given = given
+        self.expected = expected
+        Exception.__init__(self.__doc__.format(**self.__dict__))
+
+
+class Rows(object):
+    """
+    row-based data
+    """
+
+    array = OrderedDict
 
-class Dataset(object):
-    """
-    rows of data
-    """
+    def __init__(self, columns, *rows):
+        """
+        columns -- column labels
+        """
+        self.column_names = columns
+        self.rows = []
+
+        for row in rows:
+            self += row
+
+    def __iadd__(self, row):
+        """add a labeled row"""
+        if len(row) != len(self.columns_names):
+            raise ColumnNumberException(len(row), len(self.columns_names))
+        self.rows.append(self.array(zip(self.columns_names, row)))
+
+    def __len__(self):
+        return len(self.rows)
+
+    def __getitem__(self, item):
+        return self.rows[item]