Delphi Regular Expression Syntax (9) Critical matching

Match right Var Reg:tperlregex;
 
  BEGIN REG: = Tperlregex.create (nil); Reg. Subject: = ' Delphi 6; Delphi 7; Delphi 2007;
  Delphi Net '; Reg. RegEx: = ' Delphi (? =2007) '; ? = Reg.
  Replacement: = '; Reg.
 
  ReplaceAll; ShowMessage (Reg. Subject); Back: Delphi 6; Delphi 7; 2007;
Delphi Net Freeandnil (reg);
 
End
Do not match the right Var Reg:tperlregex;
 
  BEGIN REG: = Tperlregex.create (nil); Reg. Subject: = ' Delphi 6; Delphi 7; Delphi 2007;
  Delphi Net '; Reg. RegEx: = ' Delphi ' (?! 2007) ';
  // ?! Reg.
  Replacement: = '; Reg.
 
  ReplaceAll; ShowMessage (Reg. Subject); Returns: 6; 7; Delphi 2007;
Net Freeandnil (REG);
 
End
Match left Var Reg:tperlregex;
 
  BEGIN REG: = Tperlregex.create (nil); Reg.
  Subject: = ' 111, 222,￥333,￥444 '; Reg. RegEx: = ' (? <=￥) \d{3} '; ? <= Reg.
  Replacement: = '; Reg.
 
  ReplaceAll; ShowMessage (Reg. Subject);
Return: 111, 222,￥,￥ Freeandnil (reg);
 
End
does not match left Var Reg:tperlregex;
 
  BEGIN REG: = Tperlregex.create (nil); Reg. SubjECT: = ' 111, 222,￥333,￥444 '; Reg. RegEx: = ' (? <!￥) \d{3} ';
  ? <! Reg.
  Replacement: = '; Reg.
 
  ReplaceAll; ShowMessage (Reg. Subject);
return:,￥333,￥444 Freeandnil (REG); End