如何在不使用CSV文件的情况下将JSON数据动态转换为csv格式

import json
import csv

def json_to_csv(json_data):
    data = json.loads(json_data)
    csv_data = ""

    # 获取所有列名
    columns = set()
    for item in data:
        columns.update(item.keys())

    # 写入列名
    csv_data += ",".join(columns) + "\n"

    # 写入数据
    for item in data:
        row = []
        for column in columns:
            row.append(str(item.get(column, "")))
        csv_data += ",".join(row) + "\n"

    return csv_data

# 示例JSON数据
json_data = '[{"name": "John", "age": 30, "city": "New York"}, {"name": "Alice", "age": 25, "city": "London"}]'

# 转换为CSV格式
csv_data = json_to_csv(json_data)

# 打印结果
print(csv_data)

name,age,city
John,30,New York
Alice,25,London