From 163058f1f17a89a43bf832db7329dbfe69b02362 Mon Sep 17 00:00:00 2001
From: rasbt <se.raschka@me.com>
Date: Sun, 15 Jun 2014 23:23:19 -0400
Subject: [PATCH] contain method

---
 ...y_differences_between_python_2_and_3.ipynb | 263 +++++++++++++++++-
 1 file changed, 261 insertions(+), 2 deletions(-)

diff --git a/tutorials/key_differences_between_python_2_and_3.ipynb b/tutorials/key_differences_between_python_2_and_3.ipynb
index 19d8a8c..a1afba9 100644
--- a/tutorials/key_differences_between_python_2_and_3.ipynb
+++ b/tutorials/key_differences_between_python_2_and_3.ipynb
@@ -1,7 +1,7 @@
 {
  "metadata": {
   "name": "",
-  "signature": "sha256:7d8ee5c733199e70a4c5c71b6dfd0953ab5e6c33c6a0c7ef50dce07b4d56ae32"
+  "signature": "sha256:a91d66ae5e233f325b262961102505a8bdaee3ad1a251f061dee9cd68c0aaeac"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -872,11 +872,270 @@
        "output_type": "pyerr",
        "traceback": [
         "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[0;31mNameError\u001b[0m                                 Traceback (most recent call last)",
-        "\u001b[0;32m<ipython-input-8-5d8f9b79ea70>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mxrange\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;36m10\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
+        "\u001b[0;32m<ipython-input-5-5d8f9b79ea70>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mxrange\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;36m10\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
         "\u001b[0;31mNameError\u001b[0m: name 'xrange' is not defined"
        ]
       }
      ],
+     "prompt_number": 5
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "<a id='contains'></a>\n",
+      "<br>\n",
+      "<br>\n"
+     ]
+    },
+    {
+     "cell_type": "heading",
+     "level": 3,
+     "metadata": {},
+     "source": [
+      "The `__contain__` method for `range` objects in Python 3"
+     ]
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "Another thing worth mentioning is that `range` got a \"new\" `__contains__` method in Python 3.x (thanks to [yegle](), who pointed this out).  The `__contains__` method can speedup \"look-ups\" in Python 3.x `range` significantly for integer and bolean types.\n"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "x = 10000000"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "def val_in_range(x, val):\n",
+      "    if val in range(x):\n",
+      "        return True\n",
+      "    else:\n",
+      "        return False"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [],
+     "prompt_number": 10
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "def val_in_xrange(x, val):\n",
+      "    if val in range(x):\n",
+      "        return True\n",
+      "    else:\n",
+      "        return False"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [],
+     "prompt_number": 5
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "print('Python', python_version())\n",
+      "assert(val_in_range(x, x/2) == True)\n",
+      "assert(val_in_range(x, x//2) == True)\n",
+      "%timeit val_in_range(x, x/2)\n",
+      "%timeit val_in_range(x, x//2)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Python 3.3.5\n",
+        "1 loops, best of 3: 751 ms per loop"
+       ]
+      },
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "\n",
+        "1000000 loops, best of 3: 1.21 \u00b5s per loop"
+       ]
+      },
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "\n"
+       ]
+      }
+     ],
+     "prompt_number": 11
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "Based on the `timeit` results above, you see that the execution for the \"look up\" was about 60,000 faster when it was of an integer type rather than a float. However, since Python 2.x's `range` or `xrange` doesn't have a `__contains__` method, the \"look-up speed\" wouldn't be that much different for integers or floats:"
+     ]
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "<br>"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "print 'Python', python_version()\n",
+      "assert(val_in_xrange(x, x/2.0) == True)\n",
+      "assert(val_in_xrange(x, x/2) == True)\n",
+      "%timeit val_in_xrange(x, x/2.0)\n",
+      "%timeit val_in_xrange(x, x/2)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Python 2.7.7\n",
+        "1 loops, best of 3: 661 ms per loop"
+       ]
+      },
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "\n",
+        "1 loops, best of 3: 564 ms per loop"
+       ]
+      },
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "\n"
+       ]
+      }
+     ],
+     "prompt_number": 6
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "<br>"
+     ]
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "Below the \"proofs\" that the `__contain__` method wasn't added to Python 2.x yet:"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "print('Python', python_version())\n",
+      "range.__contains__"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Python 3.4.1\n"
+       ]
+      },
+      {
+       "metadata": {},
+       "output_type": "pyout",
+       "prompt_number": 2,
+       "text": [
+        "<slot wrapper '__contains__' of 'range' objects>"
+       ]
+      }
+     ],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "print 'Python', python_version()\n",
+      "range.__contains__"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Python 2.7.7\n"
+       ]
+      },
+      {
+       "ename": "AttributeError",
+       "evalue": "'builtin_function_or_method' object has no attribute '__contains__'",
+       "output_type": "pyerr",
+       "traceback": [
+        "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[0;31mAttributeError\u001b[0m                            Traceback (most recent call last)",
+        "\u001b[0;32m<ipython-input-7-05327350dafb>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[1;32m      1\u001b[0m \u001b[0;32mprint\u001b[0m \u001b[0;34m'Python'\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mpython_version\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 2\u001b[0;31m \u001b[0mrange\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0m__contains__\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
+        "\u001b[0;31mAttributeError\u001b[0m: 'builtin_function_or_method' object has no attribute '__contains__'"
+       ]
+      }
+     ],
+     "prompt_number": 7
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "print 'Python', python_version()\n",
+      "xrange.__contains__"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "Python 2.7.7\n"
+       ]
+      },
+      {
+       "ename": "AttributeError",
+       "evalue": "type object 'xrange' has no attribute '__contains__'",
+       "output_type": "pyerr",
+       "traceback": [
+        "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[0;31mAttributeError\u001b[0m                            Traceback (most recent call last)",
+        "\u001b[0;32m<ipython-input-8-7d1a71bfee8e>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[1;32m      1\u001b[0m \u001b[0;32mprint\u001b[0m \u001b[0;34m'Python'\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mpython_version\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 2\u001b[0;31m \u001b[0mxrange\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0m__contains__\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
+        "\u001b[0;31mAttributeError\u001b[0m: type object 'xrange' has no attribute '__contains__'"
+       ]
+      }
+     ],
      "prompt_number": 8
     },
     {