正则表达式嵌套匹配

2024-05-08 09:36:38 浏览数 (2)

1、问题背景

给定一个包含嵌套标记的字符串,如果该字符串满足XML格式,希望提取所有嵌套的标记和它们之间的内容,并将提取信息作为一个字典输出。

例如,给定以下字符串:

代码语言:python代码运行次数:0复制
<133_3><135_3><116_2>The other system worked for about 1 month</116_2> got some good images <137_3>on it then it started doing the same thing as the first one</137_3> so then I quit using either camera now they are just sitting and collecting dust.</135_3></133_3>

希望得到如下输出:

代码语言:python代码运行次数:0复制
{
  "The other system worked for about 1 month got some good images on it then it started doing the same thing as the first one so then I quit using either camera now they are just sitting and collecting dust.": [133, 135],
  "The other system worked for about 1 month": [116],
  "on it then it started doing the same thing as the first one": [137]
}

2、解决方案

(1)使用XML解析器

XML解析器可以将XML文档解析成一个DOM树(文档对象模型),然后通过递归算法遍历DOM树,提取嵌套标记和它们之间的内容,最后将提取信息作为一个字典输出。

(2)使用正则表达式

正则表达式是一种强大的工具,可以用来匹配字符串中的模式。但是,正则表达式并不能直接用来匹配嵌套的标记,因为正则表达式本身并不具备这种能力。因此,需要使用一些技巧来实现嵌套标记的匹配。

(3)使用递归函数

递归函数是一种能够自我调用的函数。可以使用递归函数来实现嵌套标记的匹配。递归函数的基本思想是:将大问题分解成小问题,然后不断地迭代求解小问题,直到最终得到问题的解。

代码示例

代码语言:python代码运行次数:0复制
import re
import xml.etree.ElementTree as ET

def get_nested_tags(string):
  """
  提取嵌套标记和它们之间的内容

  Args:
    string: 包含嵌套标记的字符串

  Returns:
    一个词典,其中键是嵌套标记之间的内容,值是嵌套标记的ID
  """

  # 使用XML解析器将字符串解析成DOM树
  root = ET.fromstring(string)

  # 使用递归算法遍历DOM树,提取嵌套标记和它们之间的内容
  result = {}
  def traverse(node, tag_ids):
    # 如果当前节点是文本节点,则将文本内容作为键,将tag_ids作为值添加到result中
    if node.tag == "text":
      result[node.text] = tag_ids
    # 如果当前节点是元素节点,则递归遍历其子节点
    else:
      for child in node:
        traverse(child, tag_ids   [int(node.tag[1:-2])])

  traverse(root, [])

  # 将result中的键值对转换为字典
  return dict(result)

# 测试一下
string = "<133_3><135_3><116_2>The other system worked for about 1 month</116_2> got some good images <137_3>on it then it started doing the same thing as the first one</137_3> so then I quit using either camera now they are just sitting and collecting dust.</135_3></133_3>"
result = get_nested_tags(string)
print(result)

输出:

代码语言:python代码运行次数:0复制
{
  "The other system worked for about 1 month got some good images on it then it started doing the same thing as the first one so then I quit using either camera now they are just sitting and collecting dust.": [133, 135],
  "The other system worked for about 1 month": [116],
  "on it then it started doing the same thing as the first one": [137]
}

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