total_price = 0
book_count = 0

with open("library.txt", "r", encoding="utf-8") as file:
    for line in file:
        # 去除行尾的换行符并分割数据
        parts = line.strip().split("-")
        if len(parts) == 3:
            title, author, price = parts
            try:
                # 将价格转换为浮点数
                total_price += float(price)
                book_count += 1
            except ValueError:
                print(f"警告：'{title}'的价格格式不正确")

# 计算平均价格
if book_count > 0:
    average_price = total_price / book_count
    print(f"图书总数：{book_count}")
    print(f"平均价格：{average_price:.2f}")
else:
    print("没有找到有效的图书信息")

from collections import defaultdict

# 用于存储每个分类的图书信息
category_data = defaultdict(lambda: {'count': 0, 'total_price': 0})

# 读取文件并统计
try:
    with open("library_extended.txt", "r", encoding="utf-8") as file:
        for line in file:
            parts = line.strip().split("-")
            if len(parts) == 4:
                title, author, price, category = parts
                try:
                    price_float = float(price)
                    category_data[category]['count'] += 1
                    category_data[category]['total_price'] += price_float
                except ValueError:
                    print(f"警告：'{title}'的价格格式不正确")

    # 将统计结果写入文件
    with open("category_stats.txt", "w", encoding="utf-8") as output_file:
        output_file.write("分类,图书数量,平均价格\n")
        
        for category, data in category_data.items():
            count = data['count']
            avg_price = data['total_price'] / count if count > 0 else 0
            output_file.write(f"{category},{count},{avg_price:.2f}\n")
            
    print("统计结果已写入category_stats.txt文件")
except FileNotFoundError:
    print("错误：找不到library_extended.txt文件")

import csv
import json

try:
    # 读取CSV文件
    books = []
    with open("books_data.csv", "r", encoding="utf-8", newline="") as csv_file:
        reader = csv.DictReader(csv_file)
        row_count = 0
        
        for row in reader:
            try:
                # 处理每一行数据
                book = {
                    "title": row.get("书名", ""),
                    "author": row.get("作者", ""),
                    "price": float(row.get("价格", "0")) if row.get("价格") else 0,
                    "year": int(row.get("出版年份", "0")) if row.get("出版年份") else 0
                }
                books.append(book)
                row_count += 1
            except ValueError as e:
                print(f"警告：第{row_count+1}行数据格式不正确 - {e}")
                row_count += 1

    # 写入JSON文件
    with open("books_data.json", "w", encoding="utf-8") as json_file:
        json.dump(books, json_file, ensure_ascii=False, indent=4)
        
    print(f"成功将{len(books)}条图书信息从CSV转换为JSON格式")
except FileNotFoundError:
    print("错误：找不到books_data.csv文件")
except Exception as e:
    print(f"发生错误：{e}")

import csv
import os
from datetime import datetime

def add_borrow_record(member_id, book_id):
    """添加借阅记录"""
    borrow_date = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    new_record = [member_id, book_id, borrow_date, ""]
    
    # 检查文件是否存在
    file_exists = os.path.exists("borrow_records.csv")
    
    with open("borrow_records.csv", "a", encoding="utf-8", newline="") as file:
        writer = csv.writer(file)
        # 如果文件不存在，写入表头
        if not file_exists:
            writer.writerow(["会员ID", "图书ID", "借阅日期", "归还日期"])
        writer.writerow(new_record)
    
    print(f"已添加借阅记录：会员{member_id}借阅图书{book_id}")

def return_book(member_id, book_id):
    """记录图书归还"""
    records = []
    updated = False
    return_date = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    
    try:
        with open("borrow_records.csv", "r", encoding="utf-8", newline="") as file:
            reader = csv.reader(file)
            header = next(reader)
            records.append(header)
            
            for row in reader:
                if row[0] == member_id and row[1] == book_id and row[3] == "":
                    row[3] = return_date
                    updated = True
                records.append(row)
        
        if updated:
            with open("borrow_records.csv", "w", encoding="utf-8", newline="") as file:
                writer = csv.writer(file)
                writer.writerows(records)
            print(f"已记录归还：会员{member_id}归还图书{book_id}")
        else:
            print(f"未找到会员{member_id}借阅图书{book_id}的未归还记录")
    except FileNotFoundError:
        print("错误：借阅记录文件不存在")

def query_member_records(member_id):
    """查询会员的借阅记录"""
    found = False
    try:
        with open("borrow_records.csv", "r", encoding="utf-8", newline="") as file:
            reader = csv.DictReader(file)
            print(f"会员{member_id}的借阅记录：")
            print("="*60)
            print(f"{'图书ID':<10}{'借阅日期':<20}{'归还日期':<20}")
            print("="*60)
            
            for row in reader:
                if row["会员ID"] == member_id:
                    return_date = row["归还日期"] if row["归还日期"] else "未归还"
                    print(f"{row['图书ID']:<10}{row['借阅日期']:<20}{return_date:<20}")
                    found = True
            
            if not found:
                print("没有找到该会员的借阅记录")
    except FileNotFoundError:
        print("错误：借阅记录文件不存在")

# 测试功能
if __name__ == "__main__":
    # 添加借阅记录
    add_borrow_record("M001", "B001")
    add_borrow_record("M001", "B002")
    add_borrow_record("M002", "B003")
    
    # 查询会员记录
    query_member_records("M001")
    
    # 归还图书
    return_book("M001", "B001")
    
    # 再次查询会员记录
    query_member_records("M001")