Extracción de parte de una cadena

[dec]

Hola,

Ahí van un par de funciones que logré a partir de cierto Hilo, que, aunque he buscado, no consigo encontrar. Se trataba sobre el número "RUT" (creo recordar) de Chile y la solución la proporcionó Casimiro: en ella se basan estas funciones, que, repito, no sé si te servirán en todo caso:

Código Delphi [-]
 { ············································································ }
 
 function QuitarLetras(const cadena: string) : string;
 var
   i: integer;
 begin
   for i := 1 to Length(cadena) do
     if cadena[i] in ['0'..'9'] then
       Result := Result + cadena[i];
 end;
 
 { ············································································ }
 
 function QuitarNumeros(const cadena: string) : string;
 var
   i: integer;
 begin
   for i := 1 to Length(cadena) do
     if not (cadena[i] in ['0'..'9']) then
       Result := Result + cadena[i];
 end;
 
 { ············································································ }