Python Starter Course — Farewell + Full Notes

import random

def read_int(prompt: str) -> int:
    """Safely read an integer from the user."""
    while True:
        s = input(prompt).strip()
        if s.isdigit() or (s.startswith("-") and s[1:].isdigit()):
            return int(s)
        print("Please enter a valid integer.")

def play_guess_game():
    print("=== Number Guess Game ===")
    print("I am thinking of a number between 1 and 100.")

    secret = random.randint(1, 100)
    attempts = 0

    while True:
        guess = read_int("Your guess: ")
        attempts += 1

        if guess < secret:
            print("Too low! Try again.")
        elif guess > secret:
            print("Too high! Try again.")
        else:
            print(f"Correct! You guessed it in {attempts} attempts.")
            break

    print("Thanks for playing! 🎉")

if __name__ == "__main__":
    play_guess_game()

import json
from typing import Dict, Any

DB_FILE = "studentdb.json"

def load_db() -> Dict[str, Dict[str, Any]]:
    """Load database from a JSON file. Returns empty DB if file not found/corrupt."""
    try:
        with open(DB_FILE, "r", encoding="utf-8") as f:
            data = json.load(f)
        # Ensure it's the expected type (dict of dicts)
        if isinstance(data, dict):
            return data
        return {}
    except FileNotFoundError:
        return {}
    except Exception:
        # If JSON is invalid or unexpected error, we start clean to avoid crash.
        return {}

def save_db(db: Dict[str, Dict[str, Any]]) -> None:
    """Save database to a JSON file."""
    with open(DB_FILE, "w", encoding="utf-8") as f:
        json.dump(db, f, ensure_ascii=False, indent=2)

def read_nonempty(prompt: str) -> str:
    while True:
        s = input(prompt).strip()
        if s:
            return s
        print("Input cannot be empty.")

def read_int(prompt: str) -> int:
    while True:
        s = input(prompt).strip()
        if s.isdigit() or (s.startswith("-") and s[1:].isdigit()):
            return int(s)
        print("Please enter a valid integer.")

def add_student(db: Dict[str, Dict[str, Any]]) -> None:
    sid = read_nonempty("Student ID: ")
    if sid in db:
        print("This ID already exists. Use Update instead.")
        return

    name = read_nonempty("Name: ")
    clazz = read_nonempty("Class/Section (e.g., 10-A): ")
    age = read_int("Age: ")

    db[sid] = {
        "id": sid,
        "name": name,
        "class": clazz,
        "age": age
    }
    print("✅ Student added.")

def list_students(db: Dict[str, Dict[str, Any]]) -> None:
    if not db:
        print("No students found.")
        return

    print("\n--- All Students ---")
    print(f"{'ID':<10} {'Name':<22} {'Class':<10} {'Age':<5}")
    print("-" * 52)

    for sid, s in db.items():
        print(f"{sid:<10} {s.get('name',''):<22} {s.get('class',''):<10} {str(s.get('age','')):<5}")
    print("-" * 52)

def search_student(db: Dict[str, Dict[str, Any]]) -> None:
    if not db:
        print("No students found.")
        return

    q = read_nonempty("Search by ID or Name: ").lower()
    found = []

    for sid, s in db.items():
        if q in sid.lower() or q in str(s.get("name", "")).lower():
            found.append(s)

    if not found:
        print("No matching student found.")
        return

    print("\n--- Search Results ---")
    for s in found:
        print(f"ID: {s.get('id')} | Name: {s.get('name')} | Class: {s.get('class')} | Age: {s.get('age')}")

def update_student(db: Dict[str, Dict[str, Any]]) -> None:
    sid = read_nonempty("Enter ID to update: ")
    if sid not in db:
        print("Student not found.")
        return

    s = db[sid]
    print("Leave blank to keep current value.\n")

    name = input(f"Name ({s.get('name')}): ").strip()
    clazz = input(f"Class/Section ({s.get('class')}): ").strip()
    age_s = input(f"Age ({s.get('age')}): ").strip()

    if name:
        s["name"] = name
    if clazz:
        s["class"] = clazz
    if age_s:
        if age_s.isdigit() or (age_s.startswith("-") and age_s[1:].isdigit()):
            s["age"] = int(age_s)
        else:
            print("Invalid age. Keeping old value.")

    db[sid] = s
    print("✅ Student updated.")

def delete_student(db: Dict[str, Dict[str, Any]]) -> None:
    sid = read_nonempty("Enter ID to delete: ")
    if sid not in db:
        print("Student not found.")
        return

    confirm = read_nonempty(f"Type YES to delete {sid}: ")
    if confirm.upper() == "YES":
        del db[sid]
        print("🗑️ Student deleted.")
    else:
        print("Delete cancelled.")

def menu():
    db = load_db()

    while True:
        print("\n=== StudentDB Menu ===")
        print("1) Add Student")
        print("2) List Students")
        print("3) Search Student")
        print("4) Update Student")
        print("5) Delete Student")
        print("6) Save & Exit")
        print("7) Exit without Saving")

        choice = read_nonempty("Choose (1-7): ")

        if choice == "1":
            add_student(db)
        elif choice == "2":
            list_students(db)
        elif choice == "3":
            search_student(db)
        elif choice == "4":
            update_student(db)
        elif choice == "5":
            delete_student(db)
        elif choice == "6":
            save_db(db)
            print(f"✅ Saved to {DB_FILE}. Goodbye!")
            break
        elif choice == "7":
            print("Goodbye!")
            break
        else:
            print("Invalid choice. Try again.")

if __name__ == "__main__":
    menu()