Add type-guided refactorings exercise

Author: AliQassab

prep-exercises/type_guided_refactorings.py

@@ -0,0 +1,55 @@
+from dataclasses import dataclass
+from typing import Optional
+
+# Before refactoring - unclear types
+def process_user_data(data):
+    name = data[0]
+    age = data[1]
+    email = data[2] if len(data) > 2 else None
+    
+    if age < 18:
+        return None
+    
+    return f"{name} ({age}): {email or 'no email'}"
+
+
+# After refactoring - clear types
+@dataclass
+class User:
+    name: str
+    age: int
+    email: Optional[str] = None
+
+def is_adult(user: User) -> bool:
+    return user.age >= 18
+
+def format_user_info(user: User) -> str:
+    email_str = user.email if user.email else "no email"
+    return f"{user.name} ({user.age}): {email_str}"
+
+def process_user(user: User) -> Optional[str]:
+    if not is_adult(user):
+        return None
+    return format_user_info(user)
+
+
+# Testing old version
+print(process_user_data(("Alice", 25, "alice@example.com")))
+print(process_user_data(("Bob", 16)))
+
+# Testing new version
+user1 = User("Alice", 25, "alice@example.com")
+user2 = User("Bob", 16)
+
+print(process_user(user1))
+print(process_user(user2))
+
+
+# Another example
+def get_value(key: str, data: dict[str, int]) -> Optional[int]:
+    return data.get(key)
+
+sample_data = {"a": 1, "b": 2}
+result = get_value("a", sample_data)
+if result is not None:
+    print(f"Found: {result}")