regex - 正则表达式:多行,非贪婪匹配,直到可选字符串
问题描述
使用 Go 的正则表达式,我试图提取一组预定义的有序键值(多行)对,其最后一个元素可能是原始文本中的可选元素,例如,
Key1:
SomeValue1
MoreValue1
Key2:
SomeValue2
MoreValue2
OptionalKey3:
SomeValue3
MoreValue3
(在这里,我想将所有值提取为命名组)
如果我使用默认的贪婪模式(?s:Key1:\n(?P<Key1>.*)Key2:\n(?P<Key2>.*)(?:OptionalKey3:\n(?P<OptionalKey3>.*))?)
,它永远不会看到 OptionalKey3 并将其余文本匹配为 Key2。
如果我使用非贪婪模式(?s:Key1:\n(?P<Key1>.*)Key2:\n(?P<Key2>.*?)(?:OptionalKey3:\n(?P<OptionalKey3>.*))?)
,它甚至看不到 SomeValue2 并立即停止:https ://regex101.com/r/QE2g3o/1
有没有办法可以选择匹配 OptionalKey3 同时也能够捕获所有其他的?
解决方案
利用
(?s)\AKey1:\n(?P<Key1>.*)Key2:\n(?P<Key2>.*?)(?:OptionalKey3:\n(?P<OptionalKey3>.*))?\z
请参阅正则表达式证明。
解释
--------------------------------------------------------------------------------
(?s) set flags for this block (with . matching
\n) (case-sensitive) (with ^ and $
matching normally) (matching whitespace
and # normally)
--------------------------------------------------------------------------------
\A the beginning of the string
--------------------------------------------------------------------------------
Key1: 'Key1:'
--------------------------------------------------------------------------------
\n '\n' (newline)
--------------------------------------------------------------------------------
(?P<Key1> group and capture to "Key1":
--------------------------------------------------------------------------------
.* any character (0 or more times (matching
the most amount possible))
--------------------------------------------------------------------------------
) end of "Key1"
--------------------------------------------------------------------------------
Key2: 'Key2:'
--------------------------------------------------------------------------------
\n '\n' (newline)
--------------------------------------------------------------------------------
(?P<Key2> group and capture to "Key2":
--------------------------------------------------------------------------------
.*? any character (0 or more times (matching
the least amount possible))
--------------------------------------------------------------------------------
) end of "Key2"
--------------------------------------------------------------------------------
(?: group, but do not capture (optional
(matching the most amount possible)):
--------------------------------------------------------------------------------
OptionalKey3: 'OptionalKey3:'
--------------------------------------------------------------------------------
\n '\n' (newline)
--------------------------------------------------------------------------------
(?P<OptionalKey3> group and capture to "OptionalKey3":
--------------------------------------------------------------------------------
.* any character (0 or more times
(matching the most amount possible))
--------------------------------------------------------------------------------
) end of "OptionalKey3"
--------------------------------------------------------------------------------
)? end of grouping
--------------------------------------------------------------------------------
\z the end of the string
推荐阅读
- git - 如何在 git remote 上更新用户名和密码?
- javascript - 复制谷歌日历事件弹出面板的相同位置功能
- node.js - 如何热模块替换我正在服务器端开发的本地 npm 包呈现反应,node.js 应用程序,例如在 cezerin
- python-3.x - 在 TensorFlow 中使用多个 GPU 使用 pb 模型进行推理
- typescript - 打字稿接口:可选但不是未定义
- php - Mysql 和 php 数据库连接
- node.js - 安装 .env 模块后节点/反应,“fs”错误
- c# - 比较两个数组并从第二个数组中删除相同(相交)的值
- html - Angular 7 + Material:在表单数据中使用多个 mat-checkbox 时,只有在与它们交互后才将它们加载到字段中
- java - 是否可以在 jpa AttributeConverter 中获取 @Convert 注释的字段?