Sample code for the Duck typing article

lpozo · lpozo · commit 4640068dedcc · 2024-02-07T14:03:49.000+01:00
diff --git a/duck-typing-python/README.md b/duck-typing-python/README.md
@@ -0,0 +1,3 @@
+# Duck Typing in Python: Writing Flexible and Decoupled Code
+
+This folder provides the code examples for the Real Python tutorial [Duck Typing in Python: Writing Flexible and Decoupled Code](https://realpython.com/duck-typing-python/).
diff --git a/duck-typing-python/birds.py b/duck-typing-python/birds.py
@@ -0,0 +1,22 @@
+class Duck:
+    def swim(self):
+        print("Duck is swimming.")
+
+    def fly(self):
+        print("Duck is flying.")
+
+
+class Swan:
+    def swim(self):
+        print("Swan is swimming.")
+
+    def fly(self):
+        print("Swan is flying.")
+
+
+class Albatross:
+    def swim(self):
+        print("Albatross is swimming.")
+
+    def fly(self):
+        print("Albatross is flying.")
diff --git a/duck-typing-python/cars_abc.py b/duck-typing-python/cars_abc.py
@@ -0,0 +1,42 @@
+from abc import ABC, abstractmethod
+
+
+class Vehicle(ABC):
+    def __init__(self, make, model, color):
+        self.make = make
+        self.model = model
+        self.color = color
+
+    @abstractmethod
+    def start(self):
+        raise NotImplementedError("This method must be implemented")
+
+    @abstractmethod
+    def stop(self):
+        raise NotImplementedError("This method must be implemented")
+
+    @abstractmethod
+    def drive(self):
+        raise NotImplementedError("This method must be implemented")
+
+
+class Car(Vehicle):
+    def start(self):
+        print("Car is starting")
+
+    def stop(self):
+        print("Car is stopping")
+
+    def drive(self):
+        print("Car is driving")
+
+
+class Truck(Vehicle):
+    def start(self):
+        print("Truck is starting")
+
+    def stop(self):
+        print("Truck is stopping")
+
+    def drive(self):
+        print("Truck is driving")
diff --git a/duck-typing-python/cars_duck.py b/duck-typing-python/cars_duck.py
@@ -0,0 +1,30 @@
+class Car:
+    def __init__(self, make, model, color):
+        self.make = make
+        self.model = model
+        self.color = color
+
+    def start(self):
+        print("Car is starting")
+
+    def stop(self):
+        print("Car is stopping")
+
+    def drive(self):
+        print("Car is driving")
+
+
+class Truck:
+    def __init__(self, make, model, color):
+        self.make = make
+        self.model = model
+        self.color = color
+
+    def start(self):
+        print("Truck is starting")
+
+    def stop(self):
+        print("Truck is stopping")
+
+    def drive(self):
+        print("Truck is driving")
diff --git a/duck-typing-python/file.csv b/duck-typing-python/file.csv
@@ -0,0 +1,3 @@
+name,age,job
+John,25,Engineer
+Jane,22,Designer
diff --git a/duck-typing-python/file.json b/duck-typing-python/file.json
@@ -0,0 +1,12 @@
+[
+    {
+        "name": "John",
+        "age": 25,
+        "job": "Engineer"
+    },
+    {
+        "name": "Jane",
+        "age": 22,
+        "job": "Designer"
+    }
+]
diff --git a/duck-typing-python/file.txt b/duck-typing-python/file.txt
@@ -0,0 +1,6 @@
+John
+25
+Engineer
+Jane
+22
+Designer
diff --git a/duck-typing-python/iteration.py b/duck-typing-python/iteration.py
@@ -0,0 +1,10 @@
+numbers = [1, 2, 3, 4]
+person = ("Jane", 25, "Python Dev")
+letters = "abcdef"
+ordinals = {"one": "first", "two": "second", "three": "third"}
+even_digits = {2, 4, 6, 8}
+collections = [numbers, person, letters, ordinals, even_digits]
+
+for collection in collections:
+    for value in collection:
+        print(value)
diff --git a/duck-typing-python/mean.py b/duck-typing-python/mean.py
@@ -0,0 +1,5 @@
+from collections.abc import Collection
+
+
+def mean(sample: Collection) -> float:
+    return sum(sample) / len(sample)
diff --git a/duck-typing-python/queues.py b/duck-typing-python/queues.py
@@ -0,0 +1,24 @@
+from collections import deque
+
+
+class Queue:
+    def __init__(self):
+        self._elements = deque()
+
+    def enqueue(self, element):
+        self._elements.append(element)
+
+    def dequeue(self):
+        return self._elements.popleft()
+
+    def __iter__(self):
+        return iter(self._elements)
+
+    def __len__(self):
+        return len(self._elements)
+
+    def __reversed__(self):
+        return reversed(self._elements)
+
+    def __contains__(self, element):
+        return element in self._elements
diff --git a/duck-typing-python/readers.py b/duck-typing-python/readers.py
@@ -0,0 +1,47 @@
+import csv
+import json
+from itertools import batched
+
+
+class TextFileReader:
+    def __init__(self, filename):
+        self.filename = filename
+
+    def read(self):
+        with open(self.filename) as f:
+            result = []
+            for batch in batched(f.readlines(), 3):
+                record = {}
+                record["name"] = batch[0].strip()
+                record["age"] = batch[1].strip()
+                record["job"] = batch[2].strip()
+                result.append(record)
+            return result
+
+
+class CSVReader:
+    def __init__(self, filename):
+        self.filename = filename
+
+    def read(self):
+        with open(self.filename) as f:
+            return list(csv.DictReader(f))
+
+
+class JSONReader:
+    def __init__(self, filename):
+        self.filename = filename
+
+    def read(self):
+        with open(self.filename) as f:
+            return json.load(f)
+
+
+readers = [
+    TextFileReader("file.txt"),
+    CSVReader("file.csv"),
+    JSONReader("file.json"),
+]
+
+for reader in readers:
+    print(reader.read())
diff --git a/duck-typing-python/shapes.py b/duck-typing-python/shapes.py
@@ -0,0 +1,57 @@
+from math import pi
+from typing import Protocol
+
+
+class Shape(Protocol):
+    def area(self) -> float: ...
+
+    def perimeter(self) -> float: ...
+
+
+class Circle:
+    def __init__(self, radius: float) -> None:
+        self.radius = radius
+
+    def area(self) -> float:
+        return pi * self.radius**2
+
+    def perimeter(self) -> float:
+        return 2 * pi * self.radius
+
+
+class Square:
+    def __init__(self, side: float) -> None:
+        self.side = side
+
+    def area(self) -> float:
+        return self.side**2
+
+    def perimeter(self) -> float:
+        return 4 * self.side
+
+
+class Rectangle:
+    def __init__(self, length: float, width: float) -> None:
+        self.length = length
+        self.width = width
+
+    def area(self) -> float:
+        return self.length * self.width
+
+    def perimeter(self) -> float:
+        return 2 * (self.length + self.width)
+
+
+def describe_shape(shape: Shape) -> None:
+    print(f"{type(shape).__name__}")
+    print(f" Area: {shape.area():.2f}")
+    print(f" Perimeter: {shape.perimeter():.2f}")
+
+
+circle = Circle(3)
+square = Square(5)
+rectangle = Rectangle(4, 5)
+
+describe_shape(circle)
+describe_shape(square)
+describe_shape(rectangle)

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+# Duck Typing in Python: Writing Flexible and Decoupled Code`
	`2`	`+`
	`3`	`+This folder provides the code examples for the Real Python tutorial [Duck Typing in Python: Writing Flexible and Decoupled Code](https://realpython.com/duck-typing-python/).`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+name,age,job`
	`2`	`+John,25,Engineer`
	`3`	`+Jane,22,Designer`
-Original file line number
+Diff line change
@@ @@ -0,0 +1,6 @@ @@
 +John
 +25
 +Engineer
 +Jane
 +22
 +Designer