How I could do the oposite

Question

Basically I would like to fill an internal table. How I could do the oposite of:
check not filename is initial.
open dataset filename for output in text mode encoding non-unicode.
if sy-subrc ne 0.
  write: / msg, filename.
  exit.
endif.
loop at t_download.
  transfer t_download to filename.
endloop.
close dataset filename.

Answer 1

Thank you Narren
i assigned you points. Do you know how I could perform oposite of this complete part. Knowing the sturcture.of internal table result. Basically(after your preavious answer I have the string but how coud I de-concatenate it). Actually the opposite of:
loop at result.
CONCATENATE v_download result-knumv INTO v_download .
CONCATENATE v_download result-kposn INTO v_download SEPARATED BY
cl_abap_char_utilities=>horizontal_tab.
CONCATENATE v_download result-stunr INTO v_download SEPARATED BY
cl_abap_char_utilities=>horizontal_tab.
CONCATENATE v_download result-kschl INTO v_download SEPARATED BY
cl_abap_char_utilities=>horizontal_tab.
CONCATENATE v_download result-kwert INTO v_download SEPARATED BY
cl_abap_char_utilities=>horizontal_tab.
append v_download to t_download. clear v_download.
endloop.
check not filename is initial.
open dataset filename for output in text mode encoding non-unicode.
if sy-subrc ne 0.
  write: / msg, filename.
  exit.
endif.
loop at t_download.
  transfer t_download to filename.
endloop.
close dataset filename.