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")