{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Python types are Dynamic typed, Strong typed"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "---"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "##  Mutable and Immutable types\n",
    "- Immutable types: `number`, `string`, `tuple`\n",
    "- Mutable types: `list`, `dict`, `set`"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Whats' the different?"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Mutable"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a:  [1, 2, 3]\n",
      "b:  [1, 2, 3]\n",
      "a == b    True\n",
      "a is b    False\n"
     ]
    }
   ],
   "source": [
    "a = [1, 2, 3]  # list\n",
    "b = [1, 2, 3]  # list\n",
    "\n",
    "print(\"a: \", a)\n",
    "print(\"b: \", b)\n",
    "print(\"a == b   \", a == b)\n",
    "print(\"a is b   \", a is b)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Immutable"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "c:  abc\n",
      "d:  abc\n",
      "c == d    True\n",
      "c is d    True\n"
     ]
    }
   ],
   "source": [
    "c = \"abc\"\n",
    "d = \"abc\"\n",
    "\n",
    "print(\"c: \", c)\n",
    "print(\"d: \", d)\n",
    "print(\"c == d   \", c == d)\n",
    "print(\"c is d   \", c is d)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "---"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### The default `str` for python3 is unicode while it's byte code for python2"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "---"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Dict\n",
    "### Assign a dict"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "# method 1\n",
    "Tom = {\"name\": \"Tom\", \"age\": 40, \"gender\": \"male\"}\n",
    "\n",
    "# method 2\n",
    "Tom = dict(name=\"Tom\", age=40, gender=\"male\")\n",
    "\n",
    "# method 3\n",
    "Tom = dict(zip([\"Tom\", \"age\", \"gender\"], [\"Tom\", 40, \"male\"]))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Key checking"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "We don't know Tom's habit.\n"
     ]
    }
   ],
   "source": [
    "if not \"habit\" in Tom:\n",
    "    print(\"We don't know Tom's habit.\")"
   ]
  }
 ],
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