Added functions snippet IPython Notebook.

README.md

@@ -7,6 +7,7 @@ IPython Notebooks geared towards Python data analysis (core Python, NumPy, panda
 
 * [data structures](http://nbviewer.ipython.org/github/donnemartin/pydatanotebooks/blob/master/core/structs.ipynb)
 * [data structure utilities](http://nbviewer.ipython.org/github/donnemartin/pydatanotebooks/blob/master/core/structs_utils.ipynb)
+* [functions](http://nbviewer.ipython.org/github/donnemartin/pydatanotebooks/blob/master/core/functions.ipynb)
 * [datetime](http://nbviewer.ipython.org/github/donnemartin/pydatanotebooks/blob/master/core/datetime.ipynb)
 * [unit tests](http://nbviewer.ipython.org/github/donnemartin/pydatanotebooks/blob/master/core/unit_tests.ipynb)
 

core/functions.ipynb

@@ -0,0 +1,159 @@
+{
+ "metadata": {
+  "name": "",
+  "signature": "sha256:8c91cadf8bbcbcdd5a60fc0a89e964b846a6f5328eaa57d57afbaedda06ad3ca"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+  {
+   "cells": [
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "# Functions"
+     ]
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "* Functions as Objects\n",
+      "* Lambdas\n",
+      "* Closures\n",
+      "* \\*args, \\*\\*kwargs\n",
+      "* Currying\n",
+      "* Generators\n",
+      "* Generator Expressions"
+     ]
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "## Functions as Objects"
+     ]
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "Python treats functions as objects which can simplify data cleaning"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "%%file transform_util.py\n",
+      "import re\n",
+      "\n",
+      "\n",
+      "class TransformUtil:\n",
+      "\n",
+      "    @classmethod\n",
+      "    def remove_punctuation(cls, value):\n",
+      "        \"\"\"Removes !, #, and ?.\n",
+      "        \"\"\"        \n",
+      "        return re.sub('[!#?]', '', value) \n",
+      "\n",
+      "    @classmethod\n",
+      "    def clean_strings(cls, strings, ops): \n",
+      "        \"\"\"General purpose method to clean strings.\n",
+      "\n",
+      "        Pass in a sequence of strings and the operations to perform.\n",
+      "        \"\"\"        \n",
+      "        result = [] \n",
+      "        for value in strings: \n",
+      "            for function in ops: \n",
+      "                value = function(value) \n",
+      "            result.append(value) \n",
+      "        return result"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Overwriting transform_util.py\n"
+       ]
+      }
+     ],
+     "prompt_number": 1
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "%%file tests/test_transform_util.py\n",
+      "from nose.tools import assert_equal\n",
+      "from ..transform_util import TransformUtil\n",
+      "\n",
+      "\n",
+      "class TestTransformUtil():\n",
+      "\n",
+      "    states = [' Alabama ', 'Georgia!', 'Georgia', 'georgia', \\\n",
+      "          'FlOrIda', 'south carolina##', 'West virginia?']\n",
+      "    \n",
+      "    expected_output = ['Alabama',\n",
+      "                       'Georgia',\n",
+      "                       'Georgia',\n",
+      "                       'Georgia',\n",
+      "                       'Florida',\n",
+      "                       'South Carolina',\n",
+      "                       'West Virginia']\n",
+      "    \n",
+      "    def test_remove_punctuation(self):\n",
+      "        assert_equal(TransformUtil.remove_punctuation('!#?'), '')\n",
+      "\n",
+      "    def test_clean_strings(self):\n",
+      "        clean_ops = [str.strip, TransformUtil.remove_punctuation, str.title] \n",
+      "        output = TransformUtil.clean_strings(self.states, clean_ops)\n",
+      "        assert_equal(output, self.expected_output)\n"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Overwriting tests/test_transform_util.py\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "!nosetests tests/test_transform_util.py -v"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "core.tests.test_transform_util.TestTransformUtil.test_clean_strings ... ok\r\n",
+        "core.tests.test_transform_util.TestTransformUtil.test_remove_punctuation ... ok\r\n",
+        "\r\n",
+        "----------------------------------------------------------------------\r\n",
+        "Ran 2 tests in 0.001s\r\n",
+        "\r\n",
+        "OK\r\n"
+       ]
+      }
+     ],
+     "prompt_number": 3
+    }
+   ],
+   "metadata": {}
+  }
+ ]
+}

core/tests/test_transform_util.py

@@ -0,0 +1,24 @@
+from nose.tools import assert_equal
+from ..transform_util import TransformUtil
+
+
+class TestTransformUtil():
+
+    states = [' Alabama ', 'Georgia!', 'Georgia', 'georgia', \
+          'FlOrIda', 'south carolina##', 'West virginia?']
+    
+    expected_output = ['Alabama',
+                       'Georgia',
+                       'Georgia',
+                       'Georgia',
+                       'Florida',
+                       'South Carolina',
+                       'West Virginia']
+    
+    def test_remove_punctuation(self):
+        assert_equal(TransformUtil.remove_punctuation('!#?'), '')
+
+    def test_clean_strings(self):
+        clean_ops = [str.strip, TransformUtil.remove_punctuation, str.title] 
+        output = TransformUtil.clean_strings(self.states, clean_ops)
+        assert_equal(output, self.expected_output)

core/transform_util.py

@@ -0,0 +1,23 @@
+import re
+
+
+class TransformUtil:
+
+    @classmethod
+    def remove_punctuation(cls, value):
+        """Removes !, #, and ?.
+        """        
+        return re.sub('[!#?]', '', value) 
+
+    @classmethod
+    def clean_strings(cls, strings, ops): 
+        """General purpose method to clean strings.
+
+        Pass in a sequence of strings and the operations to perform.
+        """        
+        result = [] 
+        for value in strings: 
+            for function in ops: 
+                value = function(value) 
+            result.append(value) 
+        return result