Delphi regular expression syntax (7): matching escape characters

//? The meaning of the number is to match 0-1 times, if you need to match? How to Do var REG: tperlregex; begin REG: = tperlregex. Create (NiL); Reg. Subject: = 'Are you fine? Okay! '; Reg. RegEx: = '\? |! '; // Escape \ Reg. replacement: = '◆ '; Reg. replaceall; showmessage (Reg. subject); // return: Hello ◆ OK ◆ freeandnil (REG); end;

  // Escape characters can be used in disorder. Sometimes, problems may occur. It is best not to use VaR REG: tperlregex; begin REG: = tperlregex. create (NiL); Reg. subject: = 'How are you? Okay! '; Reg. RegEx: = '\? | \! | \ Haok'; // give unnecessary "! "And" good "added \ in this example, Reg is also normal. replacement: = '◆ '; Reg. replaceall; showmessage (Reg. subject); // return: You ◆ OK ◆ freeandnil (REG); end; {There is an option [preextra] To disable misuse, but the effect is not good}
 

Special Tables in Regular Expressions:

Special characters	Meanings in Regular Expressions	Matching character itself
^	Matches the start of a string or does not match the content in [].	\ ^
$	Matches the end of a string	\ $
(And)	Mark a subexpression	\ (And \)
[And]	Expressions matching "multiple characters"	\ [And \]
{And}	Symbol of the number of matches	\ {And \}
.	Match All characters except line breaks	\.
?	Match 0 times or 1 time	\?
+	Match at least once	\ +
*	Matches 0 times or any time	\*
|	Or	\ |
\	Escape symbol itself	\\