StringReplace字符串替換函數

 function StringReplace (const S, OldPattern, NewPattern: string; Flags: TReplaceFlags): string;

rfReplaceAll：全部替換
rfIgnoreCase：忽略大小寫

   aStr := 'This is a book, not a pen!';

   //This is two book, not a pen!只替換了第一個符合的字

   StringReplace (aStr, 'a', 'two', []);   

   //This is two book, not two pen!替換了所有符合的字

   StringReplace (aStr, 'a', 'two', [rfReplaceAll]);    

  aStr := 'This is a book, not A pen!';

   //This is two book, not A pen!只替換了符合的字(小寫a)

  StringReplace (aStr, 'a', 'two', [rfReplaceAll]);   

   //This is two book, not two pen!不管大小寫替換了所有符合的字

 StringReplace (aStr, 'a', 'two', [rfReplaceAll, rfIgnoreCase]);