From 9483e549c31bbd3fb61fdd311188ca5fc4147bb1 Mon Sep 17 00:00:00 2001
From: rasbt <se.raschka@me.com>
Date: Tue, 15 Apr 2014 16:40:35 -0400
Subject: [PATCH] mutable objects as default arguments

---
 ...t_so_obvious_python_stuff-checkpoint.ipynb | 45 +++++++++++++++----
 not_so_obvious_python_stuff.ipynb             | 45 +++++++++++++++----
 2 files changed, 74 insertions(+), 16 deletions(-)

diff --git a/.ipynb_checkpoints/not_so_obvious_python_stuff-checkpoint.ipynb b/.ipynb_checkpoints/not_so_obvious_python_stuff-checkpoint.ipynb
index 0b2dd7c..b412956 100644
--- a/.ipynb_checkpoints/not_so_obvious_python_stuff-checkpoint.ipynb
+++ b/.ipynb_checkpoints/not_so_obvious_python_stuff-checkpoint.ipynb
@@ -1,7 +1,7 @@
 {
  "metadata": {
   "name": "",
-  "signature": "sha256:611615765638a390c8e9093179758c4a23524ddcc2379aeff80e51c22031aa18"
+  "signature": "sha256:913662e78e4e0a2e83e289d74c42e197b1d5af6c2f589057de821734b0141c07"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -229,7 +229,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "Another popular example to illustrate the reuse of objects for small integers is:"
+      "#### Another popular example to illustrate the reuse of objects for small integers is:"
      ]
     },
     {
@@ -257,7 +257,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "And to illustrate the test for equality (`==`) vs. identity (`is`):"
+      "#### And to illustrate the test for equality (`==`) vs. identity (`is`):"
      ]
     },
     {
@@ -266,8 +266,8 @@
      "input": [
       "a = 'hello world!'\n",
       "b = 'hello world!'\n",
-      "print('a is b', a is b)\n",
-      "print('a == b', a == b)"
+      "print('a is b,', a is b)\n",
+      "print('a == b,', a == b)"
      ],
      "language": "python",
      "metadata": {},
@@ -276,12 +276,41 @@
        "output_type": "stream",
        "stream": "stdout",
        "text": [
-        "a is b False\n",
-        "a == b True\n"
+        "a is b, False\n",
+        "a == b, True\n"
        ]
       }
      ],
-     "prompt_number": 3
+     "prompt_number": 6
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "#### And this example shows when `==` does not necessarilu implies that two objects are the same:"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "a = float('nan')\n",
+      "print('a == a,', a == a)\n",
+      "print('a is a,', a is a)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "a == a, False\n",
+        "a is a, True\n"
+       ]
+      }
+     ],
+     "prompt_number": 7
     },
     {
      "cell_type": "markdown",
diff --git a/not_so_obvious_python_stuff.ipynb b/not_so_obvious_python_stuff.ipynb
index 0b2dd7c..b412956 100644
--- a/not_so_obvious_python_stuff.ipynb
+++ b/not_so_obvious_python_stuff.ipynb
@@ -1,7 +1,7 @@
 {
  "metadata": {
   "name": "",
-  "signature": "sha256:611615765638a390c8e9093179758c4a23524ddcc2379aeff80e51c22031aa18"
+  "signature": "sha256:913662e78e4e0a2e83e289d74c42e197b1d5af6c2f589057de821734b0141c07"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -229,7 +229,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "Another popular example to illustrate the reuse of objects for small integers is:"
+      "#### Another popular example to illustrate the reuse of objects for small integers is:"
      ]
     },
     {
@@ -257,7 +257,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "And to illustrate the test for equality (`==`) vs. identity (`is`):"
+      "#### And to illustrate the test for equality (`==`) vs. identity (`is`):"
      ]
     },
     {
@@ -266,8 +266,8 @@
      "input": [
       "a = 'hello world!'\n",
       "b = 'hello world!'\n",
-      "print('a is b', a is b)\n",
-      "print('a == b', a == b)"
+      "print('a is b,', a is b)\n",
+      "print('a == b,', a == b)"
      ],
      "language": "python",
      "metadata": {},
@@ -276,12 +276,41 @@
        "output_type": "stream",
        "stream": "stdout",
        "text": [
-        "a is b False\n",
-        "a == b True\n"
+        "a is b, False\n",
+        "a == b, True\n"
        ]
       }
      ],
-     "prompt_number": 3
+     "prompt_number": 6
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "#### And this example shows when `==` does not necessarilu implies that two objects are the same:"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "a = float('nan')\n",
+      "print('a == a,', a == a)\n",
+      "print('a is a,', a is a)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "a == a, False\n",
+        "a is a, True\n"
+       ]
+      }
+     ],
+     "prompt_number": 7
     },
     {
      "cell_type": "markdown",