03-lang-intro-c.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "# Python Language Intro (Part 3)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "## Agenda\n",
    "\n",
    "1. Language overview\n",
    "2. White space sensitivity\n",
    "3. Basic Types and Operations\n",
    "4. Statements & Control Structures\n",
    "5. Functions\n",
    "6. OOP (Classes, Methods, etc.)\n",
    "7. Immutable Sequence Types (Strings, Ranges, Tuples)\n",
    "8. Mutable data structures: Lists, Sets, Dictionaries"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "## 7. Immutable Sequence Types: Strings, Ranges, Tuples"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "Recall: All immutable sequences support the [common sequence operations](https://docs.python.org/3/library/stdtypes.html#common-sequence-operations). For many sequence types, there are constructors that allow us to create them from other sequence types."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "### Strings"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "s = 'hello'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "(\n",
    "    s[0],\n",
    "    s[1:3],\n",
    "    'e' in s,\n",
    "    s + s,\n",
    ")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "s[0] = 'j'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "t = s\n",
    "s += s # not mutating the string!"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "t, s"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "### Ranges"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "r = range(150, 10, -8)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "(\n",
    "    r[2],\n",
    "    r[3:7],\n",
    "    94 in r\n",
    ")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "### Tuples"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "(1, 2, 3)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "1, 2, 3"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "(1) # not a tuple!"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "type(_)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "(1,)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "type(_)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "1,"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "('a', 10, False, 'hello') # tuples are heterogenous "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "tuple(range(10))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "tuple('hello')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "t = tuple('hello')\n",
    "(\n",
    "    'e' in t,\n",
    "    t[::-1],\n",
    "    t * 3\n",
    ")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "## 8. Mutable data structures: Lists, Sets, Dicts"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "### Lists"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "This list supports  the [mutable sequence operations](https://docs.python.org/3/library/stdtypes.html#mutable-sequence-types) in addition to the [common sequence operations](https://docs.python.org/3/library/stdtypes.html#common-sequence-operations)."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "l = [1, 2, 1, 1, 2, 3, 3, 1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "len(l)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "l[5]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "l[1:-1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "l + ['hello', 'world']"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "l # `+` does *not* mutate the list!"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "l * 3"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "total = 0\n",
    "for x in l:\n",
    "    total += x\n",
    "total"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Lists from other things ..."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "list(range(10))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "list('hello!')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "list((1, 2, (3, 4)))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "'I love CS 331'.split()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "'apples, bananas, cats, dogs'.split(',')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# also, strings from lists of strings\n",
    "'-'.join(['a', 'e', 'i', 'o', 'u'])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "' 👏 '.join('this is a beautiful day'.split())"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "#### Mutable list operations"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "l = list('hell')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "l"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "l.append('o')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "l"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "l.append(' there')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "l"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "del l[-1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "l.extend(' there')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "l"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "l[2:7]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "del l[2:7]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "l"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "l[0:2] = 'get '"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "l"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "l[:]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "l == l[:]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "l is l[:]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Sorting lists\n",
    "\n",
    "See <https://docs.python.org/3/library/stdtypes.html#list.sort>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import random\n",
    "\n",
    "l = list(range(-10,10))\n",
    "random.shuffle(l)\n",
    "l"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "l.sort()\n",
    "l"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "random.shuffle(l)\n",
    "sorted(l)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "l"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "l.sort(reverse=True)\n",
    "l"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "l.sort(key=lambda n:abs(n))\n",
    "l"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "l.sort(key=abs, reverse=True)\n",
    "l"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "#### List comprehensions"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "[x for x in range(10)]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "adjs = ('hot', 'blue', 'quick')\n",
    "nouns = ('table', 'fox', 'sky')\n",
    "[adj + ' ' + noun for adj in adjs for noun in nouns]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "# pythagorean triples\n",
    "n = 50\n",
    "[(a,b,c) for a in range(1,n) \n",
    "         for b in range(a,n) \n",
    "         for c in range(b,n) \n",
    "         if a**2 + b**2 == c**2]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "### Sets"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "A [set](https://docs.python.org/3.7/library/stdtypes.html#set-types-set-frozenset) is a data structure that represents an *unordered* collection of unique objects (like the mathematical set). "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "s = {1, 2, 1, 1, 2, 3, 3, 1}"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "s"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "t = {2, 3, 4, 5}"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "s.union(t)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "s | t"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "s.difference(t)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "s - t"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "s.intersection(t)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "s & t"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "### Dicts"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "A [dictionary](https://docs.python.org/3/library/stdtypes.html#mapping-types-dict) is a data structure that contains a set of unique key &rarr; value mappings. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "d = {\n",
    "    'Superman':  'Clark Kent',\n",
    "    'Batman':    'Bruce Wayne',\n",
    "    'Spiderman': 'Peter Parker',\n",
    "    'Ironman':   'Tony Stark'\n",
    "}"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "d['Ironman']"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "d['Ironman'] = 'James Rhodes'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "d"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "del d['Ironman']\n",
    "d"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "for k in d:\n",
    "    print(f'{k} => {d[k]}')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "for k in d.keys():\n",
    "    print(f'{k} => {d[k]}')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "for v in d.values():\n",
    "    print(v)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "for k,v in d.items():\n",
    "    print(f'{k} => {v}')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "state": "normal"
   },
   "source": [
    "#### Dictionary comprehensions"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "{e:2**e for e in range(0,100,10)}"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "{x:y for x in range(3) for y in range(10)}"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "state": "normal"
   },
   "outputs": [],
   "source": [
    "sentence = 'a man a plan a canal panama'\n",
    "{w:w[::-1] for w in sentence.split()}"
   ]
  }
 ],
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