3. Control flow.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Control flow statements"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# 1. Conditional statements"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "![](images/conditional.png)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "if (true) {\n",
    "    \n",
    "    \n",
    "}"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "- askldjf\n",
    "    - asdf\n",
    "    - alksdjf\n",
    "- asdf"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "1 indent = 2 spaces, 4 spaces, tab, 8 spaces"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "end\n"
     ]
    }
   ],
   "source": [
    "a = False\n",
    "\n",
    "if a:\n",
    "    print(\"the value is true\")\n",
    "print(\"end\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "{\n",
    "    int a = 1\n",
    "}\n",
    "cout << a;"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "this value is 5\n"
     ]
    }
   ],
   "source": [
    "a = 5\n",
    "\n",
    "if a == 3:\n",
    "    print(\"this value is 3\")\n",
    "elif a == 5:\n",
    "    print(\"this value is 5\")\n",
    "else:\n",
    "    print(\"this value is not 3 or 5\")\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "y = B'C + AC'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "if (not b and c) or (a and not c)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Challenge:\n",
    "[Python If-Else](https://www.hackerrank.com/challenges/py-if-else)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "x: int (-inf, inf)\n",
    "G -> x\n",
    "\n",
    "a = x < 0\n",
    "b = x == 0\n",
    "c = x > 0\n",
    "\n",
    "a int b = b int c = a int c = phi\n",
    "\n",
    "a u b u c != G\n",
    "\n",
    "conditions are mutually exclusive"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Nested if-else\n",
    "\n",
    "Write a python program to input an integer from user and print:\n",
    "- -1 if integer is negative.\n",
    "- 0 if integer is zero.\n",
    "- 1 if integer is positive.\n",
    "\n",
    "What's not cool with this approach???\n",
    "\n",
    "```python\n",
    "if x < 0:\n",
    "   sign = -1\n",
    "if x == 0:\n",
    "   sign = 0\n",
    "if x > 0:\n",
    "   sign = 1\n",
    "```\n",
    "\n",
    "![](images/nested.jpeg)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "q = can profile A access profile B\n",
    "\n",
    "a = isFriend\n",
    "b = isBlocked\n",
    "c = isAdmin\n",
    "d = isMarkZuckerberg\n",
    "\n",
    "```\n",
    "a b c d q\n",
    "0 0 0 0 0\n",
    "0 0 0 1 1\n",
    "0 0 1 0 1\n",
    "0 0 1 1 1\n",
    "0 1 0 0 0\n",
    "0 1 0 1 1\n",
    "0 1 1 0 0\n",
    "0 1 1 1 1\n",
    "1 0 0 0 1\n",
    "1 0 0 1 1\n",
    "1 0 1 0 1\n",
    "1 0 1 1 1\n",
    "1 1 0 0 0\n",
    "1 1 0 1 1\n",
    "1 1 1 0 0\n",
    "1 1 1 1 1\n",
    "```\n",
    "\n",
    "```py\n",
    "if ____:\n",
    "    print(\"has access\")\n",
    "else:\n",
    "    print(\"access denied\")\n",
    "```\n",
    "\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "a = [1, 2, 3, 4, 5]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "sequence item 0: expected str instance, int found",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[0;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
      "\u001b[0;32m<ipython-input-5-d55b5fb79e95>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0;34m\",\"\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mjoin\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0ma\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[0;31mTypeError\u001b[0m: sequence item 0: expected str instance, int found"
     ]
    }
   ],
   "source": [
    "\",\".join(a)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# 2. Looping statements"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## (i) while\n",
    "\n",
    "The while statement allows you to repeatedly execute a block of statements as long as a condition is true.\n",
    "\n",
    "![](images/while-loop.png)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1\n",
      "2\n",
      "3\n",
      "4\n",
      "5\n",
      "6\n",
      "7\n",
      "8\n",
      "9\n"
     ]
    }
   ],
   "source": [
    "a = 1\n",
    "while a < 10:\n",
    "    print(a)\n",
    "    a += 1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "while battery.notDead():\n",
    "    pas"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## (ii) for\n",
    "\n",
    "The for..in statement is another looping statement which iterates over a sequence of objects i.e. go through each item in a sequence.\n",
    "\n",
    "![](images/for_loop.jpg)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {},
   "outputs": [],
   "source": [
    "name = \"jatin\""
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "<method-wrapper '__iter__' of str object at 0x111f7f070>"
      ]
     },
     "execution_count": 23,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "name.__iter__"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "<class 'str'>\n",
      "***\n",
      "j\n",
      "<class 'str'>\n",
      "a\n",
      "<class 'str'>\n",
      "t\n",
      "<class 'str'>\n",
      "i\n",
      "<class 'str'>\n",
      "n\n",
      "<class 'str'>\n"
     ]
    }
   ],
   "source": [
    "print(type(name))\n",
    "print(\"***\")\n",
    "\n",
    "for c in name:\n",
    "    print(c)\n",
    "    print(type(c))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0\n",
      "1\n",
      "2\n",
      "3\n",
      "4\n"
     ]
    }
   ],
   "source": [
    "for i in range(5):\n",
    "    print(i)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {},
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "'int' object is not iterable",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[0;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
      "\u001b[0;32m<ipython-input-28-66d1c8a32ee9>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0;32mfor\u001b[0m \u001b[0mi\u001b[0m \u001b[0;32min\u001b[0m \u001b[0;36m1\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m      2\u001b[0m     \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mi\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
      "\u001b[0;31mTypeError\u001b[0m: 'int' object is not iterable"
     ]
    }
   ],
   "source": [
    "for i in 1:\n",
    "    print(i)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 29,
   "metadata": {},
   "outputs": [],
   "source": [
    "a = range(5)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 31,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "<method-wrapper '__iter__' of range object at 0x111f57e40>"
      ]
     },
     "execution_count": 31,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "a.__iter__"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Challenge:\n",
    "Solve using **for** as well as **while** loop:\n",
    "[Loops](https://www.hackerrank.com/challenges/python-loops)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Infinite loops\n",
    "\n",
    "Beware!\n",
    "\n",
    "![](images/infinite.jpg)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Nested loops\n",
    "\n",
    "Yes! Loops can also be nested.\n",
    "\n",
    "Lets do matrix addition!"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Challenge for you!\n",
    "\n",
    "Given an integer n, print a nXn matrix with squares (outermost to innermost) having values n, then n-1 and so on.\n",
    "For example, given 5, output is:\n",
    "```\n",
    "5 5 5 5 5\n",
    "5 4 4 4 5\n",
    "5 4 3 4 5\n",
    "5 4 4 4 5 \n",
    "5 5 5 5 5\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "collapsed": true
   },
   "source": [
    "n = 7\n",
    "\n",
    "```\n",
    "7 7 7 7 7 7 7\n",
    "7 6 6 6 6 6 7\n",
    "7 6 5 5 5 6 7\n",
    "7 6 5 4 5 6 7\n",
    "7 6 5 5 5 6 7\n",
    "7 6 6 6 6 6 7\n",
    "7 7 7 7 7 7 7\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## break, continue and pass"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 33,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'aaaaaaaaaaaaaaaaaaaaaaaa'"
      ]
     },
     "execution_count": 33,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "\"aaaaaa\" * 4"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": 35,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0\n",
      "1\n",
      "2\n",
      "3\n"
     ]
    }
   ],
   "source": [
    "for i in range(5):\n",
    "    print(i) # 3\n",
    "    if i == 3: # 3\n",
    "        break"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 39,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0\n",
      "100\n",
      "1\n",
      "100\n",
      "2\n",
      "100\n",
      "3\n",
      "100\n",
      "4\n",
      "100\n"
     ]
    }
   ],
   "source": [
    "for i in [0, 1, 2, 3, 4]: # i = 2\n",
    "    print(i) # i = 2\n",
    "    i = 100 # i = 100\n",
    "    print(i) # i = 100"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 45,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "rest of the code\n"
     ]
    }
   ],
   "source": [
    "if True:\n",
    "    \"vklkjhgfgh\"\n",
    "print(\"rest of the code\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": 49,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0\n",
      "1\n",
      "2\n",
      "3\n",
      "something\n"
     ]
    }
   ],
   "source": [
    "for i in range(5):\n",
    "    print(i)\n",
    "    if i == 3:\n",
    "        break\n",
    "else:\n",
    "    print(\"something\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "![](images/break.jpg)"
   ]
  }
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