regex101: Python Match Workspace

Pro

^start of line

---the literal text ---

Negated Character Class[^\S\n]*

*matches any number of characters outside the set below:

\Sany character that is not Unicode whitespace

\na line-feed (newline) character (ASCII 10)

Negative Lookahead(?!.*\bhas joined the conversation\b)

.*any Unicode character (except for line terminators), repeated any number of times

\ba Unicode word boundary

has joined the conversationthe literal text has joined the conversation (case sensitive)

\ba Unicode word boundary

Group 1(\S.*?)

\Sany character that is not Unicode whitespace

.*?any Unicode character (except for line terminators), repeated any number of times

Negated Character Class[^\S\r]*

*matches any number of characters outside the set below:

\Sany character that is not Unicode whitespace

\ra carriage return (ASCII 13)

$end of line

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

25 tokens

Regular Expression

^---[^\S\n]*\n(?!.*\bhas joined the conversation\b)(\S.*?)[^\S\r]*$

New

(2021-07-29 01:00:00 AM BST)  
---  
peter.j.matthew has joined the conversation  
  
  

(2021-07-29 01:00:00 AM BST)  
---  
john cheung has joined the conversation  
  
  


(2021-07-29 01:11:19 AM BST)  
---  
allen.p.jonas  
Hi, james  
  
  
(2021-07-30 12:51:16 AM BST)  
---  
karren wenda  
how're you ? 
  
  
  
---  
  
* * *

Substitution

(2021-07-29 01:00:00 AM BST)  
---  
peter.j.matthew has joined the conversation  
  
  

(2021-07-29 01:00:00 AM BST)  
---  
john cheung has joined the conversation  
  
  


(2021-07-29 01:11:19 AM BST)  
---  
allen.p.jonas  
Hi, james  
  
  
(2021-07-30 12:51:16 AM BST)  
---  
karren wenda  
how're you ? 
  
  
  
---  
  
* * *