03-format_loops.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Formatting & Repetition w/Counting Loops"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Variables\n",
    "* Variable is a name assigned to a Python object \n",
    "* Can assign a variable to any Python object\n",
    "* Used as a refernce point for values that may not be known at the start of a program\n",
    "* Should be named descriptively, using underscores to separate multiple words\n",
    "* Avoid [reserved words](https://www.w3schools.com/python/python_ref_keywords.asp) \n",
    "* Avoid conventions like num1, num2\n",
    "### input()\n",
    "* input is a top level built-in function\n",
    "* Can be used to get and store values from a user\n",
    "* Can be used to introduce a pause in code execution\n",
    "* Can be thought of as a listener waiting for the enter key to be pressed\n",
    "* Data captured by input will be string data\n",
    "### Recasting\n",
    "* Transforming one object type to another\n",
    "* Commonly used transformations:\n",
    "    * int([value])\n",
    "    * float([value])\n",
    "    * str([value])\n",
    "    \n",
    "###  Operations \n",
    "* = --> assignment operator\n",
    "* == --> comparison operator for equality, \n",
    "* != --> not equal\n",
    "* <, >, <=, >=\n",
    "* += --> incrementer \n",
    "* -= --> decrementer\n",
    "* other combinations can also be used, i.e. *=, etc,"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Symbolic Constants\n",
    "* Some programming languages require you to define a variable BEFORE assigning values to it. \n",
    "* This has some advantages, mainly protects against the data being recast\n",
    "* The advantage also turns out to be somewhat of a disadvantage too\n",
    "* This type of language convention is known as \"strongly type\"\n",
    "* Strongly typed languages may also allow other modifiers such as \"constant\" to be used\n",
    "* The opposite of strongly typed is loosely typed --> Python \n",
    "* Recent updates to Python have added a Pythonic version of strongly typed called \"type hinting\" \n",
    "* However things like constants and otehr contraints cannot be strictly enforced in Python --> anti-Pythonic!\n",
    "* Instead if we have the need to introduce a constant we do it symbolically.\n",
    "* Just a variable named in all CAPS"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "TAX_RATE = .20"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Counting loops"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1\t1\n",
      "2\t4\n",
      "3\t9\n",
      "4\t16\n",
      "5\t25\n"
     ]
    }
   ],
   "source": [
    "for i in range(1,6):\n",
    "    print(f\"{i}\\t{i ** 2}\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "i"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0\n",
      "5\n",
      "10\n",
      "15\n",
      "20\n",
      "25\n",
      "30\n",
      "35\n",
      "40\n",
      "45\n"
     ]
    }
   ],
   "source": [
    "for number in range(0,50, 5):\n",
    "    print(number)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "10\n",
      "9\n",
      "8\n",
      "7\n",
      "6\n",
      "5\n",
      "4\n",
      "3\n",
      "2\n",
      "1\n",
      "0\n",
      "-1\n"
     ]
    }
   ],
   "source": [
    "for number in range(10,-2, -1):\n",
    "    print(number)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "range(10, 0, -1)"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "range(10, 0, -1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[10, 9, 8, 7, 6, 5, 4, 3, 2, 1]"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "list(range(10, 0, -1))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "fruits = [\"apple\", \"kiwi\", \"banana\"]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "apple is a fruit\n",
      "kiwi is a fruit\n",
      "banana is a fruit\n"
     ]
    }
   ],
   "source": [
    "for fruit in fruits:\n",
    "    print(f\"{fruit} is a fruit\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "3"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "len(fruits)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "len(\"hello\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "h\n",
      "e\n",
      "l\n",
      "l\n",
      "o\n"
     ]
    }
   ],
   "source": [
    "for letter in \"hello\":\n",
    "    print(letter)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# ps 3"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "deposit *= (1+r)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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