Delphi the Regular Expression syntax (7) matches an escape character

// ? The meaning of the number is matched 0-1 times, if need to match? How to do
var
  reg:tperlregex;
Begin
  Reg: = Tperlregex.create (nil);
 
  Reg. Subject: = ' How are you? It's ok! ';
  Reg. RegEx   : = ' \?|! ';//Gar with \
  Reg. Replacement: = ';
  Reg. ReplaceAll;
 
  ShowMessage (Reg. Subject); Return: How are you doing?
 
  Freeandnil (reg);
End;
 
The use of escape symbols \ is sometimes possible, but sometimes problems, it is best not to use
var
  reg:tperlregex;
Begin
  Reg: = Tperlregex.create (nil);
 
  Reg. Subject: = ' How are you? It's ok! ';
  Reg. RegEx   : = ' \?| \!| \ good '; To the unnecessary "!" and "good" added \ In this case also normal
  Reg. Replacement: = ';
  Reg. ReplaceAll;
 
  ShowMessage (Reg. Subject); Return: Are you still OK
 
  Freeandnil (reg);
End;
{There would have been an option [Preextra] to prohibit the use of chaos, but the effect is not good}

Special characters in regular expressions:

Special characters	Meaning in regular expressions	Match the character itself
^	Matches the start of a string, or does not match the content in []	\^
$	Match end of string	\$
and	To mark a child expression	\ (and \)
and	Expressions that match "multiple characters"	\[and \]
and	Symbol for number of matches	\{and \}
.	Match all characters except line breaks	\.
?	Match 0 times or 1 times	\?
+	Match at least 1 times	\+
*	Match 0 times or any time	\*
|	Or	\|
\	Escape symbol itself	\\