复杂一点的python图书管理系统

以下是一个简单的 Python 图书管理系统，包含基本的增删查改功能和文件存储。

import os

class Book:
    def __init__(self, title, author, isbn):
        self.title = title
        self.author = author
        self.isbn = isbn
    
    def __str__(self):
        return f"{self.title} by {self.author} ({self.isbn})"

class BookList:
    def __init__(self):
        self.books = []
        self.filepath = "books.txt"
        if os.path.exists(self.filepath):
            with open(self.filepath, "r") as f:
                lines = f.readlines()
                for line in lines:
                    title, author, isbn = line.strip().split(",")
                    book = Book(title, author, isbn)
                    self.books.append(book)
    
    def add_book(self, book):
        self.books.append(book)
        self.save_books()
    
    def remove_book(self, book):
        self.books.remove(book)
        self.save_books()
    
    def find_book(self, title):
        for book in self.books:
            if book.title == title:
                return book
    
    def display_books(self):
        for book in self.books:
            print(book)
    
    def save_books(self):
        with open(self.filepath, "w") as f:
            for book in self.books:
                f.write(f"{book.title},{book.author},{book.isbn}\n")

def menu():
    print("Welcome to the Book Manager!")
    print("1. Add a book")
    print("2. Remove a book")
    print("3. Find a book")
    print("4. Display all books")
    print("5. Exit")
    choice = input("Enter your choice: ")
    return choice

booklist = BookList()

while True:
    choice = menu()
    if choice == "1":
        title = input("Enter the book title: ")
        author = input("Enter the book author: ")
        isbn = input("Enter the book ISBN: ")
        book = Book(title, author, isbn)
        booklist.add_book(book)
    elif choice == "2":
        title = input("Enter the book title: ")
        book = booklist.find_book(title)
        if book:
            booklist.remove_book(book)
        else:
            print("Book not found.")
    elif choice == "3":
        title = input("Enter the book title: ")
        book = booklist.find_book(title)
        if book:
            print(book)
        else:
            print("Book not found.")
    elif choice == "4":
        booklist.display_books()
    elif choice == "5":
        print("Goodbye!")
        break
    else:
        print("Invalid choice. Please try again.")

该系统使用 Book 类表示书籍，BookList 类包含 books 列表和文件路径，以及 add_book、remove_book、find_book、display_books 和 save_books 方法。

menu 函数打印菜单并返回用户选择。在主循环中，根据用户的选择执行相应的操作。

该系统将书籍信息保存在名为 books.txt 的文件中。如果文件存在，则在程序启动时读取文件并将书籍添加到 books 列表中。每次添加、删除或修改书籍时，都会将列表写回文件中。