06.Core Python - Getting Started/08.Exceptions - 01.ipynb

{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "DIGIT_MAP = {\n",
    "    'zero': '0',\n",
    "    'one': '1',\n",
    "    'two': '2',\n",
    "    'three': '3',\n",
    "    'four':'4',\n",
    "    'five':'5'\n",
    "}"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [],
   "source": [
    "def convert(s):\n",
    "    number = ''\n",
    "    for token in s:\n",
    "        number += DIGIT_MAP[token]\n",
    "    x = int(number)\n",
    "    return x"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "1235"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "#call function\n",
    "convert('one two three five'.split())"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## modified to include try except block"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [],
   "source": [
    "def convert(s):\n",
    "    try:\n",
    "        number = ''\n",
    "        for token in s:\n",
    "            number += DIGIT_MAP[token]\n",
    "        x = int(number)\n",
    "        print(f'conversion succeeded! x={x}')\n",
    "    except KeyError:\n",
    "        print(f'conversion failed!')\n",
    "        x = -1\n",
    "    return x"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "conversion failed!\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "-1"
      ]
     },
     "execution_count": 11,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "convert('blah'.split())"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "conversion succeeded! x=34\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "34"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "convert('three four'.split())"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "'int' object is not iterable",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-13-a2c2dfc9e966>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[0mconvert\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;36m55\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;32m<ipython-input-10-794344a3c4e0>\u001b[0m in \u001b[0;36mconvert\u001b[1;34m(s)\u001b[0m\n\u001b[0;32m      2\u001b[0m     \u001b[1;32mtry\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m      3\u001b[0m         \u001b[0mnumber\u001b[0m \u001b[1;33m=\u001b[0m \u001b[1;34m''\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 4\u001b[1;33m         \u001b[1;32mfor\u001b[0m \u001b[0mtoken\u001b[0m \u001b[1;32min\u001b[0m \u001b[0ms\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m      5\u001b[0m             \u001b[0mnumber\u001b[0m \u001b[1;33m+=\u001b[0m \u001b[0mDIGIT_MAP\u001b[0m\u001b[1;33m[\u001b[0m\u001b[0mtoken\u001b[0m\u001b[1;33m]\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m      6\u001b[0m         \u001b[0mx\u001b[0m \u001b[1;33m=\u001b[0m \u001b[0mint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mnumber\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
      "\u001b[1;31mTypeError\u001b[0m: 'int' object is not iterable"
     ]
    }
   ],
   "source": [
    "convert(55)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## added TypeError in exception block"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [],
   "source": [
    "def convert(s):\n",
    "    \"\"\"convert string to integer\n",
    "    \"\"\"\n",
    "    try:\n",
    "        number = ''\n",
    "        for token in s:\n",
    "            number += DIGIT_MAP[token]\n",
    "        x = int(number)\n",
    "        print(f'conversion succeeded! x={x}')\n",
    "    except KeyError:\n",
    "        print(f'conversion failed!')\n",
    "        x = -1\n",
    "    except TypeError:\n",
    "        print(f'conversion failed!')\n",
    "        x = -1\n",
    "    return x"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "conversion failed!\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "-1"
      ]
     },
     "execution_count": 18,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "convert(55)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## clean up the code"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [],
   "source": [
    "def convert(s):\n",
    "    \"\"\"convert string to integer\n",
    "    \"\"\"\n",
    "    x = -1\n",
    "    try:\n",
    "        number = ''\n",
    "        for token in s:\n",
    "            number += DIGIT_MAP[token]\n",
    "        x = int(number)\n",
    "        print(f'conversion succeeded! x={x}')\n",
    "    except (KeyError,TypeError):\n",
    "        print(f'conversion failed!')      \n",
    "    return x"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "conversion failed!\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "-1"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "convert(55)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "conversion failed!\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "-1"
      ]
     },
     "execution_count": 23,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "convert('six eight'.split())"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "conversion succeeded! x=113\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "113"
      ]
     },
     "execution_count": 24,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "convert('one one three'.split())"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## now everyting seems working fine, remove print statement"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {},
   "outputs": [
    {
     "ename": "IndentationError",
     "evalue": "expected an indented block (<ipython-input-25-2e982a90c256>, line 11)",
     "output_type": "error",
     "traceback": [
      "\u001b[1;36m  File \u001b[1;32m\"<ipython-input-25-2e982a90c256>\"\u001b[1;36m, line \u001b[1;32m11\u001b[0m\n\u001b[1;33m    return x\u001b[0m\n\u001b[1;37m         ^\u001b[0m\n\u001b[1;31mIndentationError\u001b[0m\u001b[1;31m:\u001b[0m expected an indented block\n"
     ]
    }
   ],
   "source": [
    "def convert(s):\n",
    "    \"\"\"convert string to integer\n",
    "    \"\"\"\n",
    "    x = -1\n",
    "    try:\n",
    "        number = ''\n",
    "        for token in s:\n",
    "            number += DIGIT_MAP[token]\n",
    "        x = int(number)\n",
    "    except (KeyError,TypeError):\n",
    "    return x"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## using pass : no op, as python doesn't allow empty statements"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {},
   "outputs": [],
   "source": [
    "def convert(s):\n",
    "    \"\"\"convert string to integer\n",
    "    \"\"\"\n",
    "    x = -1\n",
    "    try:\n",
    "        number = ''\n",
    "        for token in s:\n",
    "            number += DIGIT_MAP[token]\n",
    "        x = int(number)\n",
    "    except (KeyError,TypeError):\n",
    "        pass\n",
    "    return x"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Printing out details info for exception, standard error, raise exception"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 34,
   "metadata": {},
   "outputs": [],
   "source": [
    "import sys\n",
    "from math import log\n",
    "\n",
    "def convert(s):\n",
    "    \"\"\"convert string to integer\n",
    "    \"\"\"\n",
    "    try:\n",
    "        number = ''\n",
    "        for token in s:\n",
    "            number += DIGIT_MAP[token]\n",
    "        return int(number)\n",
    "    except (KeyError,TypeError) as e:\n",
    "        print(f'Conversion Error: {e!r}', file=sys.stderr)       \n",
    "        raise\n",
    "    \n",
    "    \n",
    "def string_log(s):\n",
    "    v = convert(s)\n",
    "    return log(v)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 35,
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "Conversion Error: KeyError('six')\n"
     ]
    },
    {
     "ename": "KeyError",
     "evalue": "'six'",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mKeyError\u001b[0m                                  Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-35-0513201d23f2>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[0mstring_log\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m'six eight'\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0msplit\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;32m<ipython-input-34-7b1c347e227f>\u001b[0m in \u001b[0;36mstring_log\u001b[1;34m(s)\u001b[0m\n\u001b[0;32m     16\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m     17\u001b[0m \u001b[1;32mdef\u001b[0m \u001b[0mstring_log\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0ms\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m---> 18\u001b[1;33m     \u001b[0mv\u001b[0m \u001b[1;33m=\u001b[0m \u001b[0mconvert\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0ms\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m     19\u001b[0m     \u001b[1;32mreturn\u001b[0m \u001b[0mlog\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mv\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
      "\u001b[1;32m<ipython-input-34-7b1c347e227f>\u001b[0m in \u001b[0;36mconvert\u001b[1;34m(s)\u001b[0m\n\u001b[0;32m      8\u001b[0m         \u001b[0mnumber\u001b[0m \u001b[1;33m=\u001b[0m \u001b[1;34m''\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m      9\u001b[0m         \u001b[1;32mfor\u001b[0m \u001b[0mtoken\u001b[0m \u001b[1;32min\u001b[0m \u001b[0ms\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m---> 10\u001b[1;33m             \u001b[0mnumber\u001b[0m \u001b[1;33m+=\u001b[0m \u001b[0mDIGIT_MAP\u001b[0m\u001b[1;33m[\u001b[0m\u001b[0mtoken\u001b[0m\u001b[1;33m]\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m     11\u001b[0m         \u001b[1;32mreturn\u001b[0m \u001b[0mint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mnumber\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m     12\u001b[0m     \u001b[1;32mexcept\u001b[0m \u001b[1;33m(\u001b[0m\u001b[0mKeyError\u001b[0m\u001b[1;33m,\u001b[0m\u001b[0mTypeError\u001b[0m\u001b[1;33m)\u001b[0m \u001b[1;32mas\u001b[0m \u001b[0me\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
      "\u001b[1;31mKeyError\u001b[0m: 'six'"
     ]
    }
   ],
   "source": [
    "string_log('six eight'.split())"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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