var
  aStr: String;
begin
  aStr := 'This is a book, not a pen!';
  ShowMessage(StringReplace(aStr, 'a', 'two', []));//變為This is two book, not a pen!只替換了第一個符合的字
  ShowMessage(StringReplace(aStr, 'a', 'two', [rfReplaceAll]));//變為This is two book, not two pen!替換了所有符合的字
  aStr := 'This is a book, not A pen!';
  ShowMessage(StringReplace(aStr, 'a', 'two', [rfReplaceAll]));//變為This is two book, not A pen!只替換了符合的字(小寫a)
  ShowMessage(StringReplace(aStr, 'a', 'two', [rfReplaceAll, rfIgnoreCase]));//變為This is two book, not two pen!不管大小寫替換了所有符合的字
end;