自己收集的几个比较实用的Delphi字符串函数

//从右边取
function RightStr
    (Const Str: String; Size: Word): String;
begin
  if Size > Length(Str) then Size := Length(Str) ;
  RightStr := Copy(Str, Length(Str)-Size+1, Size)
end;
//从中间取
function MidStr
    (Const Str: String; From, Size: Word): String;
begin
  MidStr := Copy(Str, From, Size)
end;
//从左边取
function LeftStr
    (Const Str: String; Size: Word): String;
begin
  LeftStr := Copy(Str, 1, Size)
end;
//翻转字符串
Function Reverse(S : String): String;
Var
   i : Integer;
Begin
   Result := ‘‘;
   For i := Length(S) DownTo 1 Do
   Begin
     Result := Result + Copy(S,i,1) ;
   End;
End;
//取最后一个字串的位置
function LastPos(const SubStr: String; const S: String): Integer;
begin
   result := Pos(Reverse(SubStr), Reverse(S)) ;

   if (result <> 0) then
     result := ((Length(S) - Length(SubStr)) + 1) - result + 1;
end;