week1/Intermediate Python.ipynb

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    "# Intermediate Level Python\n",
    "\n",
    "## Getting you up to speed\n",
    "\n",
    "This course assumes that you're at an intermediate level of python. For example, you should have a decent idea what something like this might do:\n",
    "\n",
    "`yield from {book.get(\"author\") for book in books if book.get(\"author\")}`\n",
    "\n",
    "If not - then you've come to the right place! Welcome to the crash course in intermediate level python. The best way to learn is by doing!\n"
   ]
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    "## First: if you need a refresher on the foundations\n",
    "\n",
    "I'm going to defer to an AI friend for this, because these explanations are so well written with great examples. Copy and paste the code examples into a new cell to give them a try. Pick whichever section(s) you'd like to brush up on.\n",
    "\n",
    "**Python imports:**  \n",
    "https://chatgpt.com/share/672f9f31-8114-8012-be09-29ef0d0140fb\n",
    "\n",
    "**Python functions** including default arguments:  \n",
    "https://chatgpt.com/share/672f9f99-7060-8012-bfec-46d4cf77d672\n",
    "\n",
    "**Python strings**, including slicing, split/join, replace and literals:  \n",
    "https://chatgpt.com/share/672fb526-0aa0-8012-9e00-ad1687c04518\n",
    "\n",
    "**Python f-strings** including number and date formatting:  \n",
    "https://chatgpt.com/share/672fa125-0de0-8012-8e35-27918cbb481c\n",
    "\n",
    "**Python lists, dicts and sets**, including the `get()` method:  \n",
    "https://chatgpt.com/share/672fa225-3f04-8012-91af-f9c95287da8d\n",
    "\n",
    "**Python files** including modes, encoding, context managers, Path, glob.glob:  \n",
    "https://chatgpt.com/share/673b53b2-6d5c-8012-a344-221056c2f960\n",
    "\n",
    "**Python classes:**  \n",
    "https://chatgpt.com/share/672fa07a-1014-8012-b2ea-6dc679552715\n",
    "\n",
    "**Pickling Python objects and converting to JSON:**  \n",
    "https://chatgpt.com/share/673b553e-9d0c-8012-9919-f3bb5aa23e31"
   ]
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    "## With this in mind - understanding NameErrors in Python\n",
    "\n",
    "It's quite common to hit a NameError in python. With foundational knowledge, you should always feel equipped to debug a NameError and get to the bottom of it.\n",
    "\n",
    "If you're unsure how to fix a NameError, please see this [initial guide](https://chatgpt.com/share/67958312-ada0-8012-a1d3-62b3a5fcbbfc) and this [second guide with exercises](https://chatgpt.com/share/67a57e0b-0194-8012-bb50-8ea76c5995b8), and work through them both until you have high confidence.\n",
    "\n",
    "There's some repetition here, so feel free to skip it if you're already confident.\n",
    "\n",
    "## And now, on to the code!"
   ]
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    "# First let's create some things:\n",
    "\n",
    "fruits = [\"Apples\", \"Bananas\", \"Pears\"]\n",
    "\n",
    "book1 = {\"title\": \"Great Expectations\", \"author\": \"Charles Dickens\"}\n",
    "book2 = {\"title\": \"Bleak House\", \"author\": \"Charles Dickens\"}\n",
    "book3 = {\"title\": \"An Book By No Author\"}\n",
    "book4 = {\"title\": \"Moby Dick\", \"author\": \"Herman Melville\"}\n",
    "\n",
    "books = [book1, book2, book3, book4]"
   ]
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   "source": [
    "# Part 1: List and dict comprehensions"
   ]
  },
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   "source": [
    "# Simple enough to start\n",
    "\n",
    "for fruit in fruits:\n",
    "    print(fruit)"
   ]
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    "# Let's make a new version of fruits\n",
    "\n",
    "fruits_shouted = []\n",
    "for fruit in fruits:\n",
    "    fruits_shouted.append(fruit.upper())\n",
    "\n",
    "fruits_shouted"
   ]
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   "source": [
    "# You probably already know this\n",
    "# There's a nice Python construct called \"list comprehension\" that does this:\n",
    "\n",
    "fruits_shouted2 = [fruit.upper() for fruit in fruits]\n",
    "fruits_shouted2"
   ]
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    "# But you may not know that you can do this to create dictionaries, too:\n",
    "\n",
    "fruit_mapping = {fruit: fruit.upper() for fruit in fruits}\n",
    "fruit_mapping"
   ]
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    "# you can also use the if statement to filter the results\n",
    "\n",
    "fruits_with_longer_names_shouted = [fruit.upper() for fruit in fruits if len(fruit)>5]\n",
    "fruits_with_longer_names_shouted"
   ]
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    "fruit_mapping_unless_starts_with_a = {fruit: fruit.upper() for fruit in fruits if not fruit.startswith('A')}\n",
    "fruit_mapping_unless_starts_with_a"
   ]
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   "source": [
    "# Another comprehension\n",
    "\n",
    "[book['title'] for book in books]"
   ]
  },
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   "source": [
    "# This code will fail with an error because one of our books doesn't have an author\n",
    "\n",
    "[book['author'] for book in books]"
   ]
  },
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   "source": [
    "# But this will work, because get() returns None\n",
    "\n",
    "[book.get('author') for book in books]"
   ]
  },
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   "source": [
    "# And this variation will filter out the None\n",
    "\n",
    "[book.get('author') for book in books if book.get('author')]"
   ]
  },
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   "source": [
    "# And this version will convert it into a set, removing duplicates\n",
    "\n",
    "set([book.get('author') for book in books if book.get('author')])"
   ]
  },
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    "# And finally, this version is even nicer\n",
    "# curly braces creates a set, so this is a set comprehension\n",
    "\n",
    "{book.get('author') for book in books if book.get('author')}"
   ]
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    "# Part 2: Generators\n",
    "\n",
    "We use Generators in the course because AI models can stream back results.\n",
    "\n",
    "If you've not used Generators before, please start with this excellent intro from ChatGPT:\n",
    "\n",
    "https://chatgpt.com/share/672faa6e-7dd0-8012-aae5-44fc0d0ec218\n",
    "\n",
    "Try pasting some of its examples into a cell."
   ]
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    "# First define a generator; it looks like a function, but it has yield instead of return\n",
    "\n",
    "import time\n",
    "\n",
    "def come_up_with_fruit_names():\n",
    "    for fruit in fruits:\n",
    "        time.sleep(1) # thinking of a fruit\n",
    "        yield fruit"
   ]
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    "# Then use it\n",
    "\n",
    "for fruit in come_up_with_fruit_names():\n",
    "    print(fruit)"
   ]
  },
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   "source": [
    "# Here's another one\n",
    "\n",
    "def authors_generator():\n",
    "    for book in books:\n",
    "        if book.get(\"author\"):\n",
    "            yield book.get(\"author\")"
   ]
  },
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   "source": [
    "# Use it\n",
    "\n",
    "for author in authors_generator():\n",
    "    print(author)"
   ]
  },
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   "source": [
    "# Here's the same thing written with list comprehension\n",
    "\n",
    "def authors_generator():\n",
    "    for author in [book.get(\"author\") for book in books if book.get(\"author\")]:\n",
    "        yield author"
   ]
  },
  {
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   "source": [
    "# Use it\n",
    "\n",
    "for author in authors_generator():\n",
    "    print(author)"
   ]
  },
  {
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   "source": [
    "# Here's a nice shortcut\n",
    "# You can use \"yield from\" to yield each item of an iterable\n",
    "\n",
    "def authors_generator():\n",
    "    yield from [book.get(\"author\") for book in books if book.get(\"author\")]"
   ]
  },
  {
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   "source": [
    "# Use it\n",
    "\n",
    "for author in authors_generator():\n",
    "    print(author)"
   ]
  },
  {
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   "source": [
    "# And finally - we can replace the list comprehension with a set comprehension\n",
    "\n",
    "def unique_authors_generator():\n",
    "    yield from {book.get(\"author\") for book in books if book.get(\"author\")}"
   ]
  },
  {
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   "source": [
    "# Use it\n",
    "\n",
    "for author in unique_authors_generator():\n",
    "    print(author)"
   ]
  },
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    "# And for some fun - press the stop button in the toolbar when bored!\n",
    "# It's like we've made our own Large Language Model... although not particularly large..\n",
    "# See if you understand why it prints a letter at a time, instead of a word at a time. If you're unsure, try removing the keyword \"from\" everywhere in the code.\n",
    "\n",
    "import random\n",
    "import time\n",
    "\n",
    "pronouns = [\"I\", \"You\", \"We\", \"They\"]\n",
    "verbs = [\"eat\", \"detest\", \"bathe in\", \"deny the existence of\", \"resent\", \"pontificate about\", \"juggle\", \"impersonate\", \"worship\", \"misplace\", \"conspire with\", \"philosophize about\", \"tap dance on\", \"dramatically renounce\", \"secretly collect\"]\n",
    "adjectives = [\"turqoise\", \"smelly\", \"arrogant\", \"festering\", \"pleasing\", \"whimsical\", \"disheveled\", \"pretentious\", \"wobbly\", \"melodramatic\", \"pompous\", \"fluorescent\", \"bewildered\", \"suspicious\", \"overripe\"]\n",
    "nouns = [\"turnips\", \"rodents\", \"eels\", \"walruses\", \"kumquats\", \"monocles\", \"spreadsheets\", \"bagpipes\", \"wombats\", \"accordions\", \"mustaches\", \"calculators\", \"jellyfish\", \"thermostats\"]\n",
    "\n",
    "def infinite_random_sentences():\n",
    "    while True:\n",
    "        yield from random.choice(pronouns)\n",
    "        yield \" \"\n",
    "        yield from random.choice(verbs)\n",
    "        yield \" \"\n",
    "        yield from random.choice(adjectives)\n",
    "        yield \" \"\n",
    "        yield from random.choice(nouns)\n",
    "        yield \". \"\n",
    "\n",
    "for letter in infinite_random_sentences():\n",
    "    print(letter, end=\"\", flush=True)\n",
    "    time.sleep(0.02)"
   ]
  },
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   "source": [
    "# Exercise\n",
    "\n",
    "Write some python classes for the books example.\n",
    "\n",
    "Write a Book class with a title and author. Include a method has_author()\n",
    "\n",
    "Write a BookShelf class with a list of books. Include a generator method unique_authors()"
   ]
  },
  {
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   "id": "35760406-fe6c-41f9-b0c0-3e8cf73aafd0",
   "metadata": {},
   "source": [
    "# Finally\n",
    "\n",
    "Here are some intermediate level details of Classes from our AI friend, including use of type hints, inheritance and class methods. This includes a Book example.\n",
    "\n",
    "https://chatgpt.com/share/67348aca-65fc-8012-a4a9-fd1b8f04ba59"
   ]
  }
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