{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# if, else, and elif"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Stay Home'"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "rain = True\n",
    "\n",
    "if rain is True:\n",
    "    agenda = 'Stay Home'\n",
    "    \n",
    "agenda"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [],
   "source": [
    "def percentage(a, b):\n",
    "    if b == 0:\n",
    "        return None\n",
    "    \n",
    "    return round(a/b, 2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "0.1"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "percentage(10, 100)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [],
   "source": [
    "percentage(1, 0)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "I don't know you...\n"
     ]
    }
   ],
   "source": [
    "name = 'Adrian'\n",
    "\n",
    "if name == 'Annie':\n",
    "    print('Hello Annie!')\n",
    "else:\n",
    "    print(\"I don't know you...\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Hey, I know you!\n"
     ]
    }
   ],
   "source": [
    "if name in {'Adrian', 'Annie'}:\n",
    "    print('Hey, I know you!')\n",
    "\n",
    "elif name in {'Agnus', 'Angela'}:\n",
    "    print(\"Hi! I thing we've met somewhere...\")\n",
    "\n",
    "elif name in {'Boris', 'Brunhilde'} :\n",
    "    # don't talk with them\n",
    "    pass  # pass can be used in code when sintaxis requires some code, but none is needed\n",
    "\n",
    "else:\n",
    "    print(\"I don't think I know you...\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Inline `if` statements"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Adrian'"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "name = name or 'Sigizmund'\n",
    "name"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Sigizmund'"
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "name = 0\n",
    "name = name or 'Sigizmund'\n",
    "name"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "0"
      ]
     },
     "execution_count": 23,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "name = 0\n",
    "name = name if name is not None else 'Sigizmund'\n",
    "name"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Using `if` in comprehensions"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['Peter', 'Josephine']"
      ]
     },
     "execution_count": 25,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "characters = [\n",
    "    {'name': 'Peter', \"surname\": 'Rabbit'},\n",
    "    {'name': 'Josephine', 'surname': 'Rabbit'},\n",
    "    {'name': 'Michael', 'surname': 'McGregor'} \n",
    "]\n",
    "\n",
    "rabbits = [el['name'] for el in characters if el['surname'] == 'Rabbit']\n",
    "rabbits"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Loops"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## `For` loop"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0\n",
      "1\n",
      "2\n"
     ]
    }
   ],
   "source": [
    "for i in range(3):\n",
    "    print(i)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "J\n",
      "a\n",
      "c\n",
      "k\n"
     ]
    }
   ],
   "source": [
    "for char in 'Jack':\n",
    "    print(char)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "name : Jim\n",
      "surname : Hockins\n"
     ]
    }
   ],
   "source": [
    "person = {\n",
    "    'name':'Jim',\n",
    "    'surname':'Hockins'\n",
    "}\n",
    "\n",
    "for k, v in person.items():\n",
    "    print(k, ':', v)\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Itertools"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Cycle"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 31,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1 red\n",
      "2 green\n",
      "3 blue\n",
      "4 red\n",
      "5 green\n"
     ]
    }
   ],
   "source": [
    "from itertools import cycle\n",
    "colors, categories = cycle(('red', 'green', 'blue')), (1, 2, 3, 4, 5)\n",
    "\n",
    "\n",
    "for cat, color in zip(categories, colors):\n",
    "    print(cat, color)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Groupby"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 32,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Rabbit\n",
      "     Peter\n",
      "     Josephine\n",
      "McGregor\n",
      "     Michael\n"
     ]
    }
   ],
   "source": [
    "from itertools import groupby\n",
    "\n",
    "characters = [\n",
    "    {'name': 'Peter', \"surname\": 'Rabbit'},\n",
    "    {'name': 'Josephine', 'surname': 'Rabbit'},\n",
    "    {'name': 'Michael', 'surname': 'McGregor'} \n",
    "]\n",
    "\n",
    "for group_name, group in groupby(characters, lambda x: x['surname']):\n",
    "    print(group_name)\n",
    "    for el in group:\n",
    "        print('    ', el['name'])\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Product"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 33,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 33,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "from itertools import product\n",
    "w1, w2, w3, w4 = 'Hello the wonderful world!'.split()  # splits by the whitespace by default\n",
    "\n",
    "values1 = []\n",
    "for el1 in w1:\n",
    "    for el2 in w2:\n",
    "        for el3 in w3:\n",
    "            for el4 in w4:\n",
    "                values1.append(el1 + el2 + el3 + el4)\n",
    "\n",
    "\n",
    "# OR\n",
    "values2 = []\n",
    "for el1, el2, el3, el4 in product(w1, w2, w3, w4):\n",
    "    values2.append(el1 + el2 + el3 + el4)\n",
    "\n",
    "values1 == values2"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Enumeration"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 37,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1. name: Jim\n",
      "2. surname: Hockins\n"
     ]
    }
   ],
   "source": [
    "# here, 1 defines starting index\n",
    "for i, (k, v) in enumerate(person.items(), 1):\n",
    "    print(f'{i}. {k}: {v}')\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## `While` loop"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 38,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0\n",
      "1\n",
      "2\n",
      "3\n",
      "4\n"
     ]
    }
   ],
   "source": [
    "counter = 0\n",
    "while counter < 5:\n",
    "    print(counter)\n",
    "    counter += 1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 41,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Below minimum!\n",
      "Value is: 3, Samples took: 18\n"
     ]
    }
   ],
   "source": [
    "from random import randint  # built-in random values generator\n",
    "counter = 0\n",
    "minimum = 10\n",
    "\n",
    "while True:\n",
    "    value = randint(1, 100)\n",
    "    if value < minimum:\n",
    "        print('Below minimum!')\n",
    "        break\n",
    "\n",
    "    counter +=1\n",
    "\n",
    "print(f'Value is: {value}, Samples took: {counter}')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Additional functionality - break and continue\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 42,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "D\n",
      "a\n"
     ]
    }
   ],
   "source": [
    "for letter in \"Data\":\n",
    "    if letter == 't':\n",
    "        break\n",
    "    print(letter)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 43,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "D\n",
      "a\n",
      "a\n"
     ]
    }
   ],
   "source": [
    "for letter in \"Data\":\n",
    "    if letter == 't':\n",
    "        continue\n",
    "    print(letter)\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Try/except/finally"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Exceptions"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 49,
   "metadata": {},
   "outputs": [],
   "source": [
    "def _check_raise(inst, type_, text=None):\n",
    "    text = text if text is not None else f'Wrong value: requires {type} format, got {type(inst)}'\n",
    "\n",
    "    if not isinstance(inst, type_):\n",
    "        raise ValueError(text)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 45,
   "metadata": {},
   "outputs": [],
   "source": [
    "_check_raise('Hello', str)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 50,
   "metadata": {},
   "outputs": [
    {
     "ename": "ValueError",
     "evalue": "Wrong value: requires <class 'type'> format, got <class 'str'>",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m--------------------------------------------------\u001b[0m",
      "\u001b[0;31mValueError\u001b[0m       Traceback (most recent call last)",
      "\u001b[0;32m<ipython-input-50-145b6e9f288c>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0m_check_raise\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m'Hello'\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mint\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[0;32m<ipython-input-49-b95b042dc54b>\u001b[0m in \u001b[0;36m_check_raise\u001b[0;34m(inst, type_, text)\u001b[0m\n\u001b[1;32m      3\u001b[0m \u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m      4\u001b[0m     \u001b[0;32mif\u001b[0m \u001b[0;32mnot\u001b[0m \u001b[0misinstance\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0minst\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mtype_\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 5\u001b[0;31m         \u001b[0;32mraise\u001b[0m \u001b[0mValueError\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mtext\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[0;31mValueError\u001b[0m: Wrong value: requires <class 'type'> format, got <class 'str'>"
     ]
    }
   ],
   "source": [
    "_check_raise('Hello', int)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Try/Finally"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 51,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "something is wrong!\n"
     ]
    },
    {
     "ename": "ZeroDivisionError",
     "evalue": "division by zero",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m--------------------------------------------------\u001b[0m",
      "\u001b[0;31mZeroDivisionError\u001b[0mTraceback (most recent call last)",
      "\u001b[0;32m<ipython-input-51-9d5a90f4a7ec>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[1;32m      1\u001b[0m \u001b[0;32mtry\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 2\u001b[0;31m     \u001b[0mresult\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0;36m1\u001b[0m \u001b[0;34m/\u001b[0m \u001b[0;36m0\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m      3\u001b[0m \u001b[0;32mfinally\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m      4\u001b[0m     \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m'something is wrong!'\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
      "\u001b[0;31mZeroDivisionError\u001b[0m: division by zero"
     ]
    }
   ],
   "source": [
    "try:\n",
    "    result = 1 / 0\n",
    "finally:\n",
    "    print('something is wrong!')\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Try/except"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 53,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "something is wrong!\n"
     ]
    }
   ],
   "source": [
    "try:\n",
    "    result = 1 / 0\n",
    "except ZeroDivisionError:\n",
    "    print('something is wrong!')\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 59,
   "metadata": {},
   "outputs": [],
   "source": [
    "import warnings  \n",
    "# built-in library that helps warning people - similar to exceptions, but won't halt code,\n",
    "# you can also set up filter for different warning types\n",
    "\n",
    "def percentage(value, total):\n",
    "    try:\n",
    "        return 100*(value / total)\n",
    "\n",
    "    except ZeroDivisionError:\n",
    "        warnings.warn('Total cannot be zero!')\n",
    "\n",
    "    except (TypeError, KeyError) as e:\n",
    "        # Keyerror here would never occur - just used it for example\n",
    "        warnings.warn(f'Something with the wrong: {e}')\n",
    "\n",
    "    except Exception as e:\n",
    "        raise Exception(value, total, e)\n",
    "\n",
    "    finally:\n",
    "        print('Anyhow, this function was executed!')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 57,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Anyhow, this function was executed!\n"
     ]
    },
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "/Users/philippk/anaconda3/envs/py36/lib/python3.6/site-packages/ipykernel_launcher.py:10: UserWarning: Total cannot be zero!\n",
      "  # Remove the CWD from sys.path while we load stuff.\n"
     ]
    }
   ],
   "source": [
    "percentage(10, 0)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 60,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Anyhow, this function was executed!\n"
     ]
    },
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "/Users/philippk/anaconda3/envs/py36/lib/python3.6/site-packages/ipykernel_launcher.py:14: UserWarning: Something with the wrong: unsupported operand type(s) for /: 'str' and 'str'\n",
      "  \n"
     ]
    }
   ],
   "source": [
    "percentage('Hello', 'world')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# `With` statement"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 62,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Hello\n",
      "World!\n"
     ]
    }
   ],
   "source": [
    "with open('./text_file.txt', 'r') as file:\n",
    "    data = file.read()\n",
    "\n",
    "print(data)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 63,
   "metadata": {},
   "outputs": [],
   "source": [
    "try:\n",
    "    file = open('./text_file.txt', 'r').__enter__()\n",
    "    data = file.read() \n",
    "finally:\n",
    "    file.__exit__()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 64,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Hello\\nWorld!'"
      ]
     },
     "execution_count": 64,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "data"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
 "metadata": {
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