My opinion on the regular expression-processing mode

name	Description
IgnoreCase (ignoring case)	Match is not case-sensitive.
Multiline (multi-line mode)	Change the meaning of ^ and $ so that they match at the beginning and end of each line, and not just at the beginning and ending of the entire string. (In this mode, theexact meaning of $ is: match the position before \ n and the position before the end of the string.)
Singleline (single-line mode)	Change the meaning of the. To make it match every character (including newline characters \ n).
Ignorepatternwhitespace (Ignore whitespace)	Ignores non-escaped whitespace in an expression and is enabled by the #标记的注释.
Explicitcapture (Explicit capture)	Only groups that have been explicitly named are captured.

My opinion on the regular expression-processing mode