vault backup: 2025-08-04 17:52:30

Affected files: 00.00 Inbox/clean code.md
2025-08-04 17:52:30 +08:00
parent bb558476ce
commit 274dfb62ea
1 changed files with 436 additions and 4 deletions
--- a/Inbox/clean
+++ b/Inbox/clean
@@ -7,7 +7,7 @@ description:
 ---

 # 核心設計原則
-本課程遵循3Rs架構：
+遵循3Rs架構：
 1. 可讀性（Readability）：讓程式碼易於理解和維護
 2. 可重用性（Reusability）：減少重複程式碼，提高開發效率
 3. 可重構性（Refactorability）：支援模組化設計和持續改進
@@ -131,9 +131,148 @@ def process_user_data(user_data):
    logger.info(f"User {user_data['name']} processed")
 ```

+## 避免副作用與Flag參數
+Good code:
+```python
+# 無副作用、單一職責的函式
+def transform_data(data):
+    """純函式：只負責資料轉換"""
+    return processed_data
+
+def save_processed_data(data):
+    """專門負責儲存資料"""
+    save_to_disk(data)
+
+def send_processing_notification():
+    """專門負責發送通知"""
+    send_notification_email()
+
+def update_processing_count():
+    """專門負責更新計數"""
+    global last_processed_count
+    last_processed_count += 1
+```
+
+Bad code:
+```python
+# 帶有副作用和flag參數的糟糕函式
+def process_data(data, save_to_file=False, send_email=False):
+    # 處理資料
+    processed_data = transform_data(data)
+    
+    # 副作用：修改全域變數
+    global last_processed_count
+    last_processed_count += 1
+    
+    # Flag參數導致函式做多件事
+    if save_to_file:
+        save_to_disk(processed_data)
+    
+    if send_email:
+        send_notification_email()
+    
+    return processed_data
+```
+
 - **程式碼組織結構**
    - 降層原則：由上到下的閱讀順序
    - 錯誤處理：使用例外處理取代錯誤碼
+        - 這點值得商榷，業界也爭論不休，不用硬性規定，應該依實際情況決定。
+
+## 降層原則：由上到下的閱讀順序
+Good code:
+```python
+# 遵循降層原則的順序
+def main_process():
+    """主要處理流程"""
+    setup_environment()
+    result = core_logic()
+    cleanup()
+    return result
+
+def setup_environment():
+    """設定處理環境"""
+    # 設定環境
+    pass
+
+def core_logic():
+    """核心邏輯處理"""
+    return helper_function()
+
+def helper_function():
+    """輔助函式"""
+    return "helper"
+
+def cleanup():
+    """清理資源"""
+    # 清理
+    pass
+```
+
+Bad code:
+```python
+# 混亂的函式順序
+def helper_function():
+    return "helper"
+
+def main_process():
+    setup_environment()
+    result = core_logic()
+    cleanup()
+    return result
+
+def setup_environment():
+    # 設定環境
+    pass
+
+def core_logic():
+    return helper_function()
+
+def cleanup():
+    # 清理
+    pass
+```
+
+## 錯誤處理：使用例外處理取代錯誤碼
+這點值得商榷，業界也爭論不休，不用硬性規定，應該依實際情況決定。
+錯誤碼針對已知、能預測的錯誤，而例外則傾向於「不應該、不可能」的錯誤。
+
+Good code:
+```c
+# 使用例外處理
+def process_file(filename):
+    """處理檔案，使用例外處理錯誤"""
+    try:
+        with open(filename, 'r') as file:
+            content = file.read()
+            return process_content(content)
+    except FileNotFoundError:
+        raise FileProcessingError(f"檔案 {filename} 不存在")
+    except PermissionError:
+        raise FileProcessingError(f"沒有權限讀取檔案 {filename}")
+    except Exception as e:
+        raise FileProcessingError(f"處理檔案時發生錯誤: {str(e)}")
+```
+
+Bad code:
+```c
+// 使用錯誤碼的方式
+int process_file(const char* filename) {
+    FILE* file = fopen(filename, "r");
+    if (file == NULL) {
+        return -1;  // 錯誤碼
+    }
+    
+    char buffer[100];
+    if (fread(buffer, 1, sizeof(buffer), file) == 0) {
+        fclose(file);
+        return -2;  // 另一個錯誤碼
+    }
+    
+    fclose(file);
+    return 0;  // 成功
+}
+```
        
 - **註解最佳實踐**
    - 何時需要註解，何時不需要
@@ -152,6 +291,92 @@ def process_user_data(user_data):
    - **L**：里氏替換原則（LSP）
    - **I**：介面隔離原則（ISP）
    - **D**：依賴反轉原則（DIP）
+
+## 單一職責原則（SRP）
+Good code:
+```python
+class User:
+    def __init__(self, username, email):
+        self.username = username
+        self.email = email
+
+class UserRepository:
+    def save(self, user):
+        database.save(user)
+
+class EmailService:
+    def send_email(self, email, message):
+        email_service.send(email, message)
+
+class UserReportGenerator:
+    def generate_report(self, user):
+        return f"User: {user.username}, Email: {user.email}"
+```
+
+Bad code:
+```python
+class User:
+    def __init__(self, username, email):
+        self.username = username
+        self.email = email
+    
+    def save_to_database(self):
+        # 儲存使用者到資料庫
+        database.save(self)
+    
+    def send_email(self, message):
+        # 發送郵件
+        email_service.send(self.email, message)
+    
+    def generate_report(self):
+        # 產生使用者報告
+        return f"User: {self.username}, Email: {self.email}"
+```
+
+## 開放封閉原則（OCP）
+Good code:
+```python
+from abc import ABC, abstractmethod
+
+class DiscountStrategy(ABC):
+    @abstractmethod
+    def calculate_discount(self, amount):
+        pass
+
+class RegularCustomerDiscount(DiscountStrategy):
+    def calculate_discount(self, amount):
+        return amount * 0.05
+
+class PremiumCustomerDiscount(DiscountStrategy):
+    def calculate_discount(self, amount):
+        return amount * 0.10
+
+class VIPCustomerDiscount(DiscountStrategy):
+    def calculate_discount(self, amount):
+        return amount * 0.15
+
+class DiscountCalculator:
+    def __init__(self, strategy: DiscountStrategy):
+        self.strategy = strategy
+    
+    def calculate_discount(self, amount):
+        return self.strategy.calculate_discount(amount)
+```
+
+Bad code:
+```python
+class DiscountCalculator:
+    def calculate_discount(self, customer_type, amount):
+        if customer_type == "regular":
+            return amount * 0.05
+        elif customer_type == "premium":
+            return amount * 0.10
+        elif customer_type == "vip":
+            return amount * 0.15
+        else:
+            return 0
+```
+
 - **實務應用案例**
    - 每個原則的程式碼範例
    - 違反原則的常見問題
@@ -161,12 +386,144 @@ def process_user_data(user_data):
    - 策略模式：演算法替換
    - 觀察者模式：事件處理    
    - 裝飾者模式：功能擴展
+    - 還有其他的設計模式，這裡不一一列出。設計模式可以給大家一個共同的語言，溝通可以更清楚、方便。
+
+## 工廠模式：封裝物件創建
+Good code:
+```python
+from abc import ABC, abstractmethod
+
+class Transport(ABC):
+    @abstractmethod
+    def deliver(self):
+        pass
+
+class Car(Transport):
+    def deliver(self):
+        return "Delivering by car"
+
+class Bike(Transport):
+    def deliver(self):
+        return "Delivering by bike"
+
+class TransportFactory:
+    _transports = {
+        "car": Car,
+        "bike": Bike
+    }
+    
+    @classmethod
+    def create_transport(cls, transport_type):
+        transport_class = cls._transports.get(transport_type)
+        if not transport_class:
+            raise ValueError(f"Unknown transport type: {transport_type}")
+        return transport_class()
+```
+
+Bad code:
+```python
+# 直接創建物件，違反開放封閉原則
+def create_transport(transport_type):
+    if transport_type == "car":
+        return Car()
+    elif transport_type == "bike":
+        return Bike()
+    elif transport_type == "plane":
+        return Plane()
+    else:
+        raise ValueError("Unknown transport type")
+```
+
+## 策略模式：演算法替換
+Good code:
+```python
+class PaymentStrategy(ABC):
+    @abstractmethod
+    def process_payment(self, amount):
+        pass
+
+class CreditCardPayment(PaymentStrategy):
+    def process_payment(self, amount):
+        return f"Processing ${amount} via credit card"
+
+class PayPalPayment(PaymentStrategy):
+    def process_payment(self, amount):
+        return f"Processing ${amount} via PayPal"
+
+class PaymentProcessor:
+    def __init__(self, strategy: PaymentStrategy):
+        self.strategy = strategy
+    
+    def set_strategy(self, strategy: PaymentStrategy):
+        self.strategy = strategy
+    
+    def process_payment(self, amount):
+        return self.strategy.process_payment(amount)
+```
+
+Bad code:
+```python
+class PaymentProcessor:
+    def process_payment(self, amount, payment_type):
+        if payment_type == "credit_card":
+            # 信用卡處理邏輯
+            return self._process_credit_card(amount)
+        elif payment_type == "paypal":
+            # PayPal處理邏輯
+            return self._process_paypal(amount)
+        elif payment_type == "bank_transfer":
+            # 銀行轉帳處理邏輯
+            return self._process_bank_transfer(amount)
+```

 - **重構基本概念**
    - 重構定義：改善內部結構不影響外部行為
    - 重構時機：三次法則與預備性重構
    - 安全重構：依賴測試確保正確性

+## 重構定義：改善內部結構不影響外部行為
+Good code:
+```python
+# 重構後：清晰且易於維護的程式碼
+def calculate_price(items):
+    return sum(calculate_item_price(item) for item in items)
+
+def calculate_item_price(item):
+    base_price = item['price'] * item['quantity']
+    discount = get_discount_rate(item)
+    return base_price * (1 - discount)
+
+def get_discount_rate(item):
+    discount_rules = {
+        'book': lambda qty: 0.1 if qty > 10 else 0,
+        'electronics': lambda qty: 0.15 if qty > 5 else 0
+    }
+    
+    rule = discount_rules.get(item['type'], lambda qty: 0)
+    return rule(item['quantity'])
+```
+
+Bad code:
+```python
+# 重構前：複雜且難以理解的程式碼
+def calculate_price(items):
+    total = 0
+    for item in items:
+        if item['type'] == 'book':
+            if item['quantity'] > 10:
+                total += item['price'] * item['quantity'] * 0.9
+            else:
+                total += item['price'] * item['quantity']
+        elif item['type'] == 'electronics':
+            if item['quantity'] > 5:
+                total += item['price'] * item['quantity'] * 0.85
+            else:
+                total += item['price'] * item['quantity']
+        else:
+            total += item['price'] * item['quantity']
+    return total
+```
+        
 - **常用重構手法**
    - 提取方法（Extract Method）
    - 封裝成員變數（Encapsulate Field）
@@ -179,6 +536,66 @@ def process_user_data(user_data):
    - 單元測試的撰寫技巧
    - 測試覆蓋率與品質指標

+## 紅燈-綠燈-重構循環
+Good code:
+```python
+# 正確的TDD方法：先寫測試
+import pytest
+
+# 1. 紅燈：先寫失敗的測試
+def test_factorial_of_zero():
+    assert calculate_factorial(0) == 1
+
+def test_factorial_of_positive_number():
+    assert calculate_factorial(5) == 120
+
+def test_factorial_of_negative_number():
+    with pytest.raises(ValueError):
+        calculate_factorial(-1)
+
+# 2. 綠燈：寫最少的程式碼讓測試通過
+def calculate_factorial(n):
+    if n < 0:
+        raise ValueError("Factorial is not defined for negative numbers")
+    if n == 0:
+        return 1
+    
+    result = 1
+    for i in range(1, n + 1):
+        result *= i
+    return result
+
+# 3. 重構：改善程式碼品質
+def calculate_factorial(n):
+    """計算階乘值"""
+    if n < 0:
+        raise ValueError("Factorial is not defined for negative numbers")
+    
+    if n <= 1:
+        return 1
+    
+    return n * calculate_factorial(n - 1)
+```
+
+Bad code:
+```python
+# 錯誤的TDD方法：先寫實作再寫測試
+def calculate_factorial(n):
+    if n < 0:
+        return None
+    if n == 0 or n == 1:
+        return 1
+    result = 1
+    for i in range(2, n + 1):
+        result *= i
+    return result
+
+# 之後才寫測試
+def test_factorial():
+    assert calculate_factorial(5) == 120
+    assert calculate_factorial(0) == 1
+```
+
 - **專案案例分析**
    - BMI計算機Clean Code版本實作
    - 購物車系統的Clean Code改造
@@ -189,6 +606,21 @@ def process_user_data(user_data):
    - 給予建設性回饋的技巧
    - 處理團隊中程式碼品質分歧

+## 審查清單建立
+### Good
+✅ 良好的程式碧審查評論：
+- "這個函式做了太多事情，建議分解成較小的函式以提高可讀性"
+- "考慮使用更描述性的變數名稱，例如將 'data' 改為 'user_profiles'"
+- "這裡可能有空指標例外的風險，建議加上 null 檢查"
+- "很好的重構！這樣的設計更容易測試和維護"
+- "建議加上單元測試來覆蓋這個邊界情況"
+
+### Bad
+❌ 糟糕的程式碼審查評論：
+- "你的程式碼很爛"
+- "為什麼要這樣寫？"
+- "這個不對"
+- "重寫整個函式"

 # 第四階段：進階實踐
 - **效能最佳化考量**