python如何保存数据，给出代码

在Python中，有多种方式可以保存数据，常见的包括文件存储、数据库存储以及序列化技术。以下是几个常用的例子：

1. **文件存储** (文本文件、CSV、JSON等):
- 保存文本数据到文件:

     data = {"name": "John", "age": 30}
     with open("data.txt", "w") as file:
         file.write(str(data))

- 保存CSV文件:

     import csv
     data = [['Name', 'Age'], ['John', 30]]
     with open('data.csv', 'w', newline='') as csvfile:
         writer = csv.writer(csvfile)
         writer.writerows(data)

- 保存JSON文件:

     import json
     data = {"key": "value"}
     with open("data.json", "w") as file:
         json.dump(data, file)

2. **数据库存储** (如SQLite、MySQL、PostgreSQL等):
- 使用sqlite3模块:

     import sqlite3
     conn = sqlite3.connect('example.db')
     c = conn.cursor()
     c.execute('''CREATE TABLE stocks
                   (date text, trans text, symbol text, qty real, price real)''')
     c.execute("INSERT INTO stocks VALUES ('2023-01-01','BUY','AAPL',100,145.2)")
     conn.commit()
     conn.close()

3. **序列化库** (pickle, msgpack, or marshmallow):
- pickle库用于Python对象的序列化:

     import pickle
     data = {'name': 'Alice'}
     with open('data.pickle', 'wb') as handle:
         pickle.dump(data, handle)