Added a small paragraph on EAFP at the end of pres02

ipynb/pres02_basic_statements.ipynb

@@ -144,9 +144,7 @@
   {
    "cell_type": "code",
    "execution_count": 5,
-   "metadata": {
-    "collapsed": true
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "a = 4\n",
@@ -226,9 +224,7 @@
   {
    "cell_type": "code",
    "execution_count": 7,
-   "metadata": {
-    "collapsed": true
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "b = bool('1')\n",
@@ -430,9 +426,7 @@
   {
    "cell_type": "code",
    "execution_count": 15,
-   "metadata": {
-    "collapsed": true
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "# float\n",
@@ -584,7 +578,7 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "['__add__', '__class__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__mod__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmod__', '__rmul__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'capitalize', 'casefold', 'center', 'count', 'encode', 'endswith', 'expandtabs', 'find', 'format', 'format_map', 'index', 'isalnum', 'isalpha', 'isascii', 'isdecimal', 'isdigit', 'isidentifier', 'islower', 'isnumeric', 'isprintable', 'isspace', 'istitle', 'isupper', 'join', 'ljust', 'lower', 'lstrip', 'maketrans', 'partition', 'replace', 'rfind', 'rindex', 'rjust', 'rpartition', 'rsplit', 'rstrip', 'split', 'splitlines', 'startswith', 'strip', 'swapcase', 'title', 'translate', 'upper', 'zfill']\n"
+      "['__add__', '__class__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__mod__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmod__', '__rmul__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'capitalize', 'casefold', 'center', 'count', 'encode', 'endswith', 'expandtabs', 'find', 'format', 'format_map', 'index', 'isalnum', 'isalpha', 'isdecimal', 'isdigit', 'isidentifier', 'islower', 'isnumeric', 'isprintable', 'isspace', 'istitle', 'isupper', 'join', 'ljust', 'lower', 'lstrip', 'maketrans', 'partition', 'replace', 'rfind', 'rindex', 'rjust', 'rpartition', 'rsplit', 'rstrip', 'split', 'splitlines', 'startswith', 'strip', 'swapcase', 'title', 'translate', 'upper', 'zfill']\n"
      ]
     }
    ],
@@ -1126,7 +1120,6 @@
    "cell_type": "code",
    "execution_count": 40,
    "metadata": {
-    "collapsed": true,
     "slideshow": {
      "slide_type": "-"
     }
@@ -1695,9 +1688,7 @@
   {
    "cell_type": "code",
    "execution_count": 57,
-   "metadata": {
-    "collapsed": true
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "s = 'wind;temperature;pressure'"
@@ -2296,8 +2287,8 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "integer remove from the list: 9\n",
-      "shuffled list:  [13, 16, 15, 14, 5, 17, 12, 8, 11, 1, 18, 2, 10, 19, 4, 7, 0, 6, 3]\n"
+      "integer remove from the list: 19\n",
+      "shuffled list:  [9, 17, 15, 14, 1, 3, 18, 7, 6, 16, 4, 0, 12, 5, 13, 2, 11, 8, 10]\n"
      ]
     }
    ],
@@ -2343,9 +2334,9 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "[13, 16, 15, 14, 5, 17, 12, 8, 11, 1, 18, 2, 10, 19, 4, 7, 0, 6, 3]\n",
-      "[0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]\n",
-      "missing  9\n"
+      "[9, 17, 15, 14, 1, 3, 18, 7, 6, 16, 4, 0, 12, 5, 13, 2, 11, 8, 10]\n",
+      "[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18]\n",
+      "missing  18\n"
      ]
     }
    ],
@@ -2374,7 +2365,7 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "missing  9\n"
+      "missing  19\n"
      ]
     }
    ],
@@ -2395,7 +2386,7 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "missing  9\n"
+      "missing  19\n"
      ]
     }
    ],
@@ -2604,10 +2595,36 @@
     "            \n",
     "print(split_list)"
    ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "source": [
+    "### Bonus: the Easier to Ask for Forgiveness than Permission (EAFP) principle\n",
+    "\n",
+    "There are several ways to perform the previous task:\n",
+    "\n",
+    "- In the solution presented above, we `try` first the conversion of the string in number and ask for *forgiveness* if we encounter an error (by using the `except`).\n",
+    "- Or we can test if the string is a number, using for example `str.isdigit()` or `str.isdecimal()` (*asking for permission*) and do the conversion only in this case.\n",
+    "\n",
+    "Both approches will lead to the same result so it is rather a question of principle. In Python, it is generally prefered to use `try` and `except` to follow the EAFP principle.\n",
+    "In this particular case, using `try` and `except` is far easier !"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
   }
  ],
  "metadata": {
-  "celltoolbar": "Slideshow",
+  "celltoolbar": "Diaporama",
   "kernelspec": {
    "display_name": "Python 3",
    "language": "python",
@@ -2623,18 +2640,18 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.2"
+   "version": "3.6.8"
   },
   "pycharm": {
    "stem_cell": {
     "cell_type": "raw",
-    "source": [],
     "metadata": {
      "collapsed": false
-    }
+    },
+    "source": []
    }
   }
  },
  "nbformat": 4,
  "nbformat_minor": 2
-}
\ No newline at end of file
+}