用python写一个图书管理系统

好的，下面是一个简单的图书管理系统的Python代码示例：

class Book:
    def __init__(self, book_id, title, author, num_copies):
        self.book_id = book_id
        self.title = title
        self.author = author
        self.num_copies = num_copies

class Library:
    def __init__(self):
        self.books = []

    def add_book(self, book):
        self.books.append(book)

    def remove_book(self, book):
        self.books.remove(book)

    def search_book(self, title):
        for book in self.books:
            if book.title == title:
                return book
        return None

    def display_books(self):
        for book in self.books:
            print("Book ID:", book.book_id)
            print("Title:", book.title)
            print("Author:", book.author)
            print("Number of copies:", book.num_copies)

if __name__ == '__main__':
    library = Library()
    book1 = Book(1, "The Great Gatsby", "F. Scott Fitzgerald", 2)
    book2 = Book(2, "To Kill a Mockingbird", "Harper Lee", 1)
    book3 = Book(3, "1984", "George Orwell", 3)
    library.add_book(book1)
    library.add_book(book2)
    library.add_book(book3)
    library.display_books()

    search_title = "To Kill a Mockingbird"
    found_book = library.search_book(search_title)
    if found_book:
        print("Book found:")
        print("Book ID:", found_book.book_id)
        print("Title:", found_book.title)
        print("Author:", found_book.author)
        print("Number of copies:", found_book.num_copies)
    else:
        print("Book not found.")

这个代码示例定义了两个类：`Book` 和 `Library`。`Book` 类表示一本书，包含书籍的 ID、标题、作者和数量。`Library` 类表示图书馆，包含一个书籍列表和一些方法，如添加书籍、删除书籍、搜索书籍和显示所有书籍。

在 `main` 函数中，我们创建了一个图书馆对象，并向其中添加了三本书。然后，我们显示了所有书籍，并搜索了一本名为 “To Kill a Mockingbird” 的书籍，打印出了它的详细信息。