{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Loops\n",
    "\n",
    "[Source](https://github.com/iArunava/Python-TheNoTheoryGuide/)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Simple while\n",
    "# Loop runs till the condition is True\n",
    "v1 = 5\n",
    "while v1 <= 10:\n",
    "    print (v1)\n",
    "    v1 += 1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Infinite Loops\n",
    "while 1:\n",
    "    print (1)\n",
    "    \n",
    "while True:\n",
    "    print (1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# One Liner while\n",
    "v1 = 0\n",
    "while v1 <= 40: v1 += 1\n",
    "print (v1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "v1 = 2\n",
    "++v1\n",
    "++v1\n",
    "print (v1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Terminate loop on a certain user input\n",
    "# Note: The loop will break only when the user inputs 100\n",
    "v1 = 1\n",
    "while v1 != 100:\n",
    "    v1 = int(input(\"Enter new v1: \"))\n",
    "    print (\"v1 modified to: \" + str(v1))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# 'break' -> breaks out of loop, doesn't execute any statement after it\n",
    "while 1:\n",
    "    v1 = int(input())\n",
    "    if v1 == 100: \n",
    "        break;\n",
    "    print (v1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# 'continue' -> continues to next iteration, skips all statements after it for that iteration\n",
    "# Note: When 'v1' < 100 the last print statement is skipped and the control moves to the next iteration\n",
    "while 1:\n",
    "    print (\"Iteration begins\")\n",
    "    v1 = int(input())\n",
    "    if v1 == 100:\n",
    "        break;\n",
    "    elif v1 < 100:\n",
    "        print (\"v1 less than 100\")\n",
    "        continue;\n",
    "    print (\"Iteration complete\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# while with lists\n",
    "l1 = [\"Jennifer\", 12, \"Python\", 'A', 56, 'B', 2.12, \"Scarlett\"]\n",
    "l2 = []\n",
    "i = 0\n",
    "while i < len(l1):\n",
    "    if type(l1[i]) == int:\n",
    "        l2.append(l1[i])\n",
    "    i += 1\n",
    "print (l2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Removing all instances of a specific value in list\n",
    "l1 = ['A', 'B', 'C', 'D', 'A', 'E', 'Q', 'A', 'Z', 'A', 'Q', 'D', 'A']\n",
    "while 'A' in l1: l1.remove('A')\n",
    "print (l1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Filing a dictionary\n",
    "d1 = {}\n",
    "while 1:\n",
    "    key   = input(\"Enter a key: \")\n",
    "    value = input(\"Enter a value: \")\n",
    "    d1[key] = value;\n",
    "    if input(\"exit? \") == \"yes\": break;\n",
    "print (d1)"
   ]
  }
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