SDC Types Rework

sprint-5/01-predict.py

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+def half(value):
+    return value / 2
+
+def double(value):
+    return value * 2
+
+def second(value):
+    return value[1]
+
+# 1. Predict what you think will happen with each of the following functions
+# 2. Then, test it, and explain in your own words what is actually happening and why
+# (feel free to comment out lines if you think they cause errors or crashes while testing)
+
+print(half(22))
+# Prediction:
+# What actually happens and why:
+
+print(half("22"))
+# Prediction:
+# What actually happens and why:
+
+print(double(22))
+# Prediction:
+# What actually happens and why:
+
+print(double("22"))
+# Prediction:
+# What actually happens and why:
+
+print(second(22))
+# Prediction:
+# What actually happens and why:
+
+print(second(0x16))
+# Prediction:
+# What actually happens and why:
+
+print(second("22"))
+# Prediction:
+# What actually happens and why:

sprint-5/02-playcomputer.js

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+import process from "node:process";
+import readline from "node:readline";
+
+const rl = readline.createInterface({
+	input: process.stdin,
+	output: process.stdout,
+});
+
+rl.question("What URL should we fetch?\n> ", async (url) => {
+	const response = await fetch(url);
+	if (!response.ok) {
+		if (response.body.toLowerCase().includes("permission")) {
+			console.error("You didn't have permission to get that URL");
+		} else {
+			console.error(`The request failed - body: ${response.body}`);
+		}
+		process.exit(1);
+	}
+
+	const contents = await response.json();
+
+	console.log(contents);
+
+	rl.close();
+});
+
+// Task: Leave a comment on any line that you can see has some errors explaining what you think the problem is

sprint-5/03-fix.py

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+def double(number):
+    return number * 3
+
+print(double(10))
+
+# Task:
+# What is the bug here?
+# How could you fix it?
+# Are there multiple possible ways to fix it?

sprint-5/04-addmypy.py

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+def open_account(balances, name, amount):
+    balances[name] = amount
+
+def sum_balances(accounts):
+    total = 0
+    for name, pence in accounts.items():
+        print(f"{name} had balance {pence}")
+        total += pence
+    return total
+
+def format_pence_as_string(total_pence):
+    if total_pence < 100:
+        return f"{total_pence}p"
+    pounds = int(total_pence / 100)
+    pence = total_pence % 100
+    return f"£{pounds}.{pence:02d}"
+
+balances = {
+    "Sima": 700,
+    "Linn": 545,
+    "Georg": 831,
+}
+
+open_account("Tobi", 9.13)
+open_account("Olya", "£7.13")
+
+total_pence = sum_balances(balances)
+total_string = format_pence_as_str(total_pence)
+
+print(f"The bank accounts total {total_string}")
+
+# TASK
+# This code contains bugs related to types. They are bugs mypy can catch.
+#
+# 1. Read this code to understand what it's trying to do.
+# 2. Install and set up mypy in a python virtual environment
+# 3. Add type annotations everywhere appropriate
+# 4. Run `mypy 04-addmypy.py`, and fix any errors
+# 5. When you're confident all of the type annotations are correct, and the bugs are fixed, run the code and check it works.

sprint-5/05-predict.py

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+imran = {
+  "name": "Imran",
+  "age": 22,
+  "preferred_operating_system": "Ubuntu",
+}
+
+eliza = {
+  "name": "Eliza",
+  "age": 34,
+  "preferred_operating_system": "Arch Linux",
+}
+
+
+print(imran["name"])
+print(imran["address"])
+
+# Task:
+# Try running mypy on this file and see what happens
+# Predict what do you think will happen when you run this task?
+# Can you explain what actualy happens?

sprint-5/06-classes.py

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+class Person:
+    def __init__(self, name: str, age: int, preferred_operating_system: str):
+        self.name = name
+        self.age = age
+        self.preferred_operating_system = preferred_operating_system
+
+imran = Person("Imran", 22, "Ubuntu")
+print(imran.name)
+print(imran.address)
+
+eliza = Person("Eliza", 34, "Arch Linux")
+print(eliza.name)
+print(eliza.address)
+
+# Task 6.1:
+# Run mypy on this code
+# Fix the code so there are no errors in mypy or when it runs
+
+# Task 6.2:
+# Create a new function in this file called likes_apple
+# It should take a person as parameter
+# It returns true if the preferred operating system is "macOS" or "iOS"
+# It should return false for any other preferred os
+# Add all the appropriate type annotations and test it has no errors in mypy
+
+# Task 6.3:
+# Compare objects and classes
+# What are some advantages and disadvantages of each?

sprint-5/07-methods.txt

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+Answer the following question:
+What is the difference between a method and a function?
+Can you give some advantages of methods over functions?
+

sprint-5/08-implement.py

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+class Person:
+    def __init__(self, name: str, age: int, preferred_operating_system: str):
+        self.name = name
+        self.age = age
+        self.preferred_operating_system = preferred_operating_system
+
+imran = Person("Imran", 22, "Ubuntu")
+print(imran.is_adult())
+
+# Task:
+# 1. Add the `drivers_license_check` free function and the `is_adult` method into the code
+# 	Make sure your code currently gives the expected output.
+#
+# 2. Change the `Person` class to take a date of birth
+#	Use the standard library's `datetime.date` class
+#	https://docs.python.org/3/library/datetime.html#datetime.date
+#	Store the `date of birth` in a field instead of `age` (it should be a `str`)
+#
+# 3. Try to run your code
+#	How does this change break your code.
+#	What kind of error do you get?
+#	Is it helpful in identifying where your next change needs to be?
+#	Type your thoughts here:
+#
+#
+#
+#
+# 4. Update the `is_adult` method so the error is fixed.
+#	Using the `drivers_license_check` function check everything runs as expected
+

sprint-5/09-dataclass.py

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+# Task 9.1:
+# Copy the code you have so far from task 08-implement.py
+# Convert this to a dataclass
+# Test that the dataclass works with mypy, with equality checks
+
+# Task 9.2:
+# Add a greeting method that says "Hello, <person name>!"
+
+# Task 9.3:
+# Read the @datatype documentation here: https://docs.python.org/3/library/dataclasses.html
+# Explain what does `frozen=True` do to the class?
+# What other options could you play around with and explore? Offer suggestions for any that would be useful here.

sprint-5/10-predict.py

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+from dataclasses import dataclass
+
+@dataclass(frozen=True)
+class Animal:
+    name: str
+    species: str
+
+@dataclass(frozen=True)
+class Person:
+    name: str
+    age: int
+
+@dataclass(frozen=True)
+class FamilyTree:
+    parent: Person
+    members: list
+
+pet = Animal(name="Gromit", species="Dog")
+fatma = Person(name="Fatma", age=4)
+aisha = Person(name="Aisha", age=6)
+imran = Person(name="Imran", age=30)
+
+family = FamilyTree(parent=imran, members=[fatma, aisha, pet])
+
+def print_family_tree(family: FamilyTree):
+    print(family.parent.name)
+    for child in family.members:
+        print(f"{child.name} ({child.age} years old)")
+
+print_family_tree(family)

sprint-5/11-fix.py

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+from dataclasses import dataclass
+from typing import List
+
+@dataclass(frozen=True)
+class Animal:
+    name: str
+    size: str
+
+@dataclass(frozen=True)
+class Person:
+    name: str
+    age: int
+
+@dataclass(frozen=True)
+class Tree[T]:
+    parent: T
+    children: List[T]
+
+    def print_tree(self):
+        print(self.parent)
+        for child in self.children:
+            print(child)
+
+fatma = Person(name="Fatma", age=4)
+aisha = Person(name="Aisha", age=6)
+imran = Person(name="Imran", age=30)
+family_tree = Tree[Person](parent=imran, children=[fatma, aisha])
+
+cats = Animal(name="Cat", size="Small")
+dogs = Animal(name="Dog", size="Medium")
+mammals = Animal(name="Mammals", size="Variable")
+species_tree = Tree[Animal](parent=mammals, children=[cats, dogs])
+
+family_tree.print_tree()
+species_tree.print_tree()
+
+# Task 11:
+# Experiment with mypy and make sure that the family tree only takes `Person` types and the species tree only takes `Animal` types.
+#
+# We are going to add printing to the above code.
+#
+# Unlike our earlier example, we want to avoid having to create two
+# separate looping methods to print out an entire tree for each datatype.
+# So we have created a single looping function within Tree that will work for any datatype.
+#
+# Currently the `Tree.print_tree()` function doesn't do anything.
+#
+# Add some appropriate methods to each of the Animal and Person classes to allow it to work.
+#
+# **Stretch task**
+#
+# Think of another type of data that can be organised into a tree.
+#
+# Add a new class for this, instantiate some variables, and have the existing `Tree` class print it out.
+# Here is an example of what should be printed out
+'''
+Imran (30 years old)
+- Fatma (4 years old)
+- Aisha (6 years old))
+Mammals (Variable size)
+- Cat (Small size)
+- Dog (Medium size)
+'''

sprint-5/12-refactor.py

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+from dataclasses import dataclass
+from typing import List
+
+@dataclass(frozen=True)
+class Person:
+    name: str
+    age: int
+    preferred_operating_system: str
+
+
+@dataclass(frozen=True)
+class Laptop:
+    id: int
+    manufacturer: str
+    model: str
+    screen_size_in_inches: float
+    operating_system: str
+
+
+def find_possible_laptops(laptops: List[Laptop], person: Person) -> List[Laptop]:
+    possible_laptops = []
+    for laptop in laptops:
+        if laptop.operating_system == person.preferred_operating_system:
+            possible_laptops.append(laptop)
+    return possible_laptops
+
+
+people = [
+    Person(name="Imran", age=22, preferred_operating_system="Ubuntu"),
+    Person(name="Eliza", age=34, preferred_operating_system="Arch Linux"),
+]
+
+laptops = [
+    Laptop(id=1, manufacturer="Dell", model="XPS", screen_size_in_inches=13, operating_system="Arch Linux"),
+    Laptop(id=2, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_system="Ubuntu"),
+    Laptop(id=3, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_system="ubuntu"),
+    Laptop(id=4, manufacturer="Apple", model="macBook", screen_size_in_inches=13, operating_system="macOS"),
+]
+
+for person in people:
+    possible_laptops = find_possible_laptops(laptops, person)
+    print(f"Possible laptops for {person.name}: {possible_laptops}")
+
+# Task 12
+#Try changing the type annotation of `Person.preferred_operating_system` from `str` to `List[str]`.
+#
+#Run mypy on the code.
+#
+#It tells us different places that our code is now wrong. Fix it to remov eany errors.
+#
+#Now we changed the types, we probably also want to _rename_ our fields to something appropriate.
+#
+#Run mypy again.
+#
+#Fix all of the places that mypy tells you need changing.
+#
+#Then, make sure the program works as you'd expect.