如何使用预查正则表达式拆分指定JSON格式字符串？

Got it, let's walk through how to split your concatenated JSON cost records using lookahead regex. Your input is a string of back-to-back AWS Cost Explorer-style objects (missing the outer array brackets), so we need a way to split exactly between each complete object without breaking the structure.

核心正则表达式 #

Here's the regex that will do the trick:

}(?=\s*{"TimePeriod":|$)

正则逻辑拆解 #

• }: 匹配单个成本记录对象的闭合大括号
• (?=\s*{"TimePeriod":|$): 这是一个正向预查，确保这个闭合大括号后面要么是：
  • 可选的空白字符（\s*）加上新记录的起始标记（{"TimePeriod":），要么是
  • 字符串结尾（$），用来处理最后一个对象

示例代码（Python） #

Let's test this with your input string (I'll fill in the truncated last object for demonstration):

import re

input_str = '''{"TimePeriod": {"Start": "2017-03-01", "End": "2017-04-01"}, "Total": {"UnblendedCost": {"Amount": "2942.25119998", "Unit": "USD"}, "UsageQuantity": {"Amount": "20835", "Unit": "Hrs"}}, "Groups": [], "Estimated": false}, {"TimePeriod": {"Start": "2017-04-01", "End": "2017-05-01"}, "Total": {"UnblendedCost": {"Amount": "2982.62609983", "Unit": "USD"}, "UsageQuantity": {"Amount": "21049", "Unit": "Hrs"}}, "Groups": [], "Estimated": false}, {"TimePeriod": {"Start": "2017-05-01", "End": "2017-06-01"}, "Total": {"UnblendedCost": {"Amount": "3010.45", "Unit": "USD"}, "UsageQuantity": {"Amount": "21200", "Unit": "Hrs"}}, "Groups": [], "Estimated": false}'''

# 使用预查正则拆分字符串
split_records = re.split(r'}(?=\s*{"TimePeriod":|$)', input_str)

# 修复拆分后丢失的闭合大括号
split_records = [record + '}' if not record.endswith('}') else record for record in split_records]

# 输出拆分结果
for idx, record in enumerate(split_records, 1):
    print(f"--- 记录 {idx} ---")
    print(record)

注意事项 #

• 如果你的输入包含截断的不完整记录（比如你原字符串里的{"TimePeriod": {"Start": "2017-05-01",...），正则会把它当作最后一个元素保留。你可以额外添加逻辑过滤掉这类不完整对象。
• 这个正则假设所有记录都以{"TimePeriod":开头，如果你的记录结构有变化，需要调整预查里的匹配模式。

内容的提问来源于stack exchange，提问作者Forrest