常用字符串处理函数

从网络上收集的一些经常会用到的字符串处理函数(基于delphi实现)

１.Get the Position of a string, starting at the end

function LastPos(SearchStr, Str: string): Integer; 
var  
  i: Integer; 
  TempStr: string; 
begin 
  Result := Pos(SearchStr, Str); 
  if Result = 0 then Exit; 
  if (Length(Str) > 0) and (Length(SearchStr) > 0) then 
  begin 
    for i := Length(Str) + Length(SearchStr) - 1 downto Result do 
    begin 
      TempStr := Copy(Str, i, Length(Str)); 
      if Pos(SearchStr, TempStr) > 0 then 
      begin 
        Result := i; 
        break; 
      end; 
    end; 
  end; 
end; 

function LastPos(SubStr, S: string): Integer; 
var 
  Found, Len, Pos: integer; 
begin 
  Pos := Length(S); 
  Len := Length(SubStr); 
  Found := 0; 
  while (Pos > 0) and (Found = 0) do  
  begin 
    if Copy(S, Pos, Len) = SubStr then 
      Found := Pos; 
    Dec(Pos); 
  end; 
  LastPos := Found; 
end; 

 

2.Search for the next occurence of a string from a certain Position

function NextPos(SearchStr, Str: string; Position: Integer): Integer; 
begin 
  Delete(Str, 1, Position - 1); 
  Result := Pos(SearchStr, upperCase(Str)); 
  if Result = 0 then Exit; 
  if (Length(Str) > 0) and (Length(SearchStr) > 0) then 
    Result := Result + Position + 1; 
end; 

3.Get the number of characters from a certain Position to the string to be searched

function NextPosRel(SearchStr, Str: string; Position: Integer): Integer; 
begin 
  Delete(Str, 1, Position - 1); 
  Result := Pos(SearchStr, UpperCase(Str)) - 1; 
end;