function Format(const Format: string; const Args: array of const): string;

Formats the series of arguments in the open array Args. Formatting is controlled by the format string Format; the results are returned as a string.

An exception will be raised if an invalid format string is specified, too few arguments are passed, or if any arguments are of the wrong type.

var
  S: String;
  I: Integer;
begin
  S := Format('%d files found', [10]);
  // S = '10 files found'

  S := Format('Filename: %s', ['file.txt']);
  // S = 'Filename: file.txt'

  I := 64;
  S := Format('%d in hex, padded to 8 digits: %.8x', [I, I]);
  // S = '64 in hex, padded to 8 digits: 00000040'
end;