Update python-data notebooks descriptions.

Author: donnemartin

README.md

@@ -226,13 +226,13 @@ IPython Notebook(s) demonstrating Python functionality geared towards data analy
 
 | Notebook | Description |
 |-----------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------|
-| [data structures](http://nbviewer.ipython.org/github/donnemartin/data-science-ipython-notebooks/blob/master/python-data/structs.ipynb) | Tuples, lists, dicts, sets. |
-| [data structure utilities](http://nbviewer.ipython.org/github/donnemartin/data-science-ipython-notebooks/blob/master/python-data/structs_utils.ipynb) | Slice, range, xrange, bisect, sort, sorted, reversed, enumerate, zip, list comprehensions. |
-| [functions](http://nbviewer.ipython.org/github/donnemartin/data-science-ipython-notebooks/blob/master/python-data/functions.ipynb) | Functions as objects, lambda functions, closures, *args, **kwargs currying, generators, generator expressions, itertools. |
-| [datetime](http://nbviewer.ipython.org/github/donnemartin/data-science-ipython-notebooks/blob/master/python-data/datetime.ipynb) | Datetime, strftime, strptime, timedelta. |
-| [logging](http://nbviewer.ipython.org/github/donnemartin/data-science-ipython-notebooks/blob/master/python-data/logs.ipynb) | Logging with RotatingFileHandler and TimedRotatingFileHandler. |
-| [pdb](http://nbviewer.ipython.org/github/donnemartin/data-science-ipython-notebooks/blob/master/python-data/pdb.ipynb) | Interactive source code debugger. |
-| [unit tests](http://nbviewer.ipython.org/github/donnemartin/data-science-ipython-notebooks/blob/master/python-data/unit_tests.ipynb) | Nose unit tests. |
+| [data structures](http://nbviewer.ipython.org/github/donnemartin/data-science-ipython-notebooks/blob/master/python-data/structs.ipynb) | Learn Python basics with tuples, lists, dicts, sets. |
+| [data structure utilities](http://nbviewer.ipython.org/github/donnemartin/data-science-ipython-notebooks/blob/master/python-data/structs_utils.ipynb) | Learn Python operations such as slice, range, xrange, bisect, sort, sorted, reversed, enumerate, zip, list comprehensions. |
+| [functions](http://nbviewer.ipython.org/github/donnemartin/data-science-ipython-notebooks/blob/master/python-data/functions.ipynb) | Learn about more advanced Python features: Functions as objects, lambda functions, closures, *args, **kwargs currying, generators, generator expressions, itertools. |
+| [datetime](http://nbviewer.ipython.org/github/donnemartin/data-science-ipython-notebooks/blob/master/python-data/datetime.ipynb) | Learn how to work with Python dates and times: datetime, strftime, strptime, timedelta. |
+| [logging](http://nbviewer.ipython.org/github/donnemartin/data-science-ipython-notebooks/blob/master/python-data/logs.ipynb) | Learn about Python logging with RotatingFileHandler and TimedRotatingFileHandler. |
+| [pdb](http://nbviewer.ipython.org/github/donnemartin/data-science-ipython-notebooks/blob/master/python-data/pdb.ipynb) | Learn how to debug in Python with the interactive source code debugger. |
+| [unit tests](http://nbviewer.ipython.org/github/donnemartin/data-science-ipython-notebooks/blob/master/python-data/unit_tests.ipynb) | Learn how to test in Python with Nose unit tests. |
 
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