如何用正则表达式筛选年份大于1999的Title参数值

问题根源 #

你用的正则"Title":"([^"]+?)".*?"Year":20[0-9]{2}之所以会匹配所有Title，是因为.*?会匹配任意字符（包括换行、其他JSON对象的内容），导致前面对象的Title会和后面对象的Year产生错误关联——比如第一个Title会匹配到最后一个对象的2018年份，从而被错误捕获。

推荐方案：用JSON解析工具处理（不推荐正则） #

正则不是处理JSON的合适工具，JSON是结构化数据，用专门的解析器能更准确、高效地完成筛选。以下是两种常见语言的实现示例：

Python示例 #

import json

# 加载JSON数据
json_data = '''
{
 "Data": {
   "Items": [
  {
    "Start": "2018-04-05T05:00:00Z",
    "End": "2018-04-05T05:30:00Z",
    "Title": "Indiana Jones and the Raiders of the Lost Ark",
    "Staff": {
      "Director": "Steven Spielberg",
      "Starring": "Harrison Ford"
    },
    "TimeZone": "UTC",
    "Id": "6ec29f07-c845-4967-9c87-716825265312",
    "Year": 1981,
    "IsNew": false,
    "ReadOnly": true
  },
  {
    "Start": "2018-06-29T12:00:00Z",
    "End": "2018-06-29T12:30:00Z",
    "Title": "The Lion King",
    "Staff": {
      "Director": "Roger Allers",
      "Starring": "James Earl Jones"
    },
    "TimeZone": "UTC",
    "Id": "9d54f04d-3554-4b61-8077-0cfb79cb86db",
    "Year": 1994,
    "IsNew": false,
    "ReadOnly": true
  },
  {
    "Start": "2018-06-01T08:00:00Z",
    "End": "2018-06-01T08:30:00Z",
    "Title": "Titanic ",
    "Staff": {
      "Director": "James Cameron",
      "Starring": "Leonardo DiCaprio"
    },
    "TimeZone": "UTC",
    "Id": "aa174cd4-da58-4bf9-a7a7-7ae562b584e6",
    "Year": 1997,
    "IsNew": false,
    "ReadOnly": true
  },
  {
    "Start": "2018-04-27T07:00:00Z",
    "End": "2018-04-27T07:30:00Z",
    "Title": "Ready Player One",
    "Staff": {
      "Director": "Steven Spielberg",
      "Starring": "Tye Sheridan"
    },
    "TimeZone": "UTC",
    "Id": "425b2969-8ec0-4943-93ce-c5a1aec148b0",
    "Year": 2018,
    "IsNew": true,
    "ReadOnly": false
  }
],
"From": 0,
"Portion": 0,
"TotalCount": 0
 },
  "RedirectViewModel": null,
 "ExceptionViewModel": null
 }
'''

data = json.loads(json_data)
# 筛选Year>1999的Title
filtered_titles = [item["Title"] for item in data["Data"]["Items"] if item["Year"] > 1999]
print(filtered_titles)

运行后会输出：['Ready Player One']

JavaScript示例 #

const jsonData = `{
 "Data": {
   "Items": [
  {
    "Start": "2018-04-05T05:00:00Z",
    "End": "2018-04-05T05:30:00Z",
    "Title": "Indiana Jones and the Raiders of the Lost Ark",
    "Staff": {
      "Director": "Steven Spielberg",
      "Starring": "Harrison Ford"
    },
    "TimeZone": "UTC",
    "Id": "6ec29f07-c845-4967-9c87-716825265312",
    "Year": 1981,
    "IsNew": false,
    "ReadOnly": true
  },
  {
    "Start": "2018-06-29T12:00:00Z",
    "End": "2018-06-29T12:30:00Z",
    "Title": "The Lion King",
    "Staff": {
      "Director": "Roger Allers",
      "Starring": "James Earl Jones"
    },
    "TimeZone": "UTC",
    "Id": "9d54f04d-3554-4b61-8077-0cfb79cb86db",
    "Year": 1994,
    "IsNew": false,
    "ReadOnly": true
  },
  {
    "Start": "2018-06-01T08:00:00Z",
    "End": "2018-06-01T08:30:00Z",
    "Title": "Titanic ",
    "Staff": {
      "Director": "James Cameron",
      "Starring": "Leonardo DiCaprio"
    },
    "TimeZone": "UTC",
    "Id": "aa174cd4-da58-4bf9-a7a7-7ae562b584e6",
    "Year": 1997,
    "IsNew": false,
    "ReadOnly": true
  },
  {
    "Start": "2018-04-27T07:00:00Z",
    "End": "2018-04-27T07:30:00Z",
    "Title": "Ready Player One",
    "Staff": {
      "Director": "Steven Spielberg",
      "Starring": "Tye Sheridan"
    },
    "TimeZone": "UTC",
    "Id": "425b2969-8ec0-4943-93ce-c5a1aec148b0",
    "Year": 2018,
    "IsNew": true,
    "ReadOnly": false
  }
],
"From": 0,
"Portion": 0,
"TotalCount": 0
 },
  "RedirectViewModel": null,
 "ExceptionViewModel": null
 }`;

const data = JSON.parse(jsonData);
const filteredTitles = data.Data.Items.filter(item => item.Year > 1999).map(item => item.Title);
console.log(filteredTitles);

运行后会输出：['Ready Player One']

迫不得已用正则的修正方案 #

如果必须用正则，需要限制Title和Year在同一个JSON对象内，避免跨对象匹配。修正后的正则如下：

"Title":"([^"]+?)"(?:(?!{)[\s\S])*?"Year":20\d{2}

正则说明 #

• (?:(?!{)[\s\S])*?：非捕获组，匹配任意字符（[\s\S]匹配所有字符包括换行），但遇到{就停止，确保只在当前JSON对象内匹配内容，避免关联到下一个对象的Year值。

注意：这种正则仅适用于结构简单的JSON，若JSON嵌套更复杂（比如对象内还有嵌套对象包含{），依然会出错，所以优先推荐用JSON解析工具。

内容的提问来源于stack exchange，提问作者Md. Ismiel Hossen Abir