Hi Jacob,
Let us say you have data in internal table lt_data
"if you know the column name
field-symbol: <fs_data> like line of lt_data.
loop at lt_data assigning <fs_data>.
<fs_data>-a = sy-tabix. "or some other number
endloop.
if you dont know the column name,
field-symbol: <fs_data> type any,
<fs_value> type any.
loop at lt_data assigning <fs_data>.
assign component 'A' of structure <fs_data> to <fs_value>.
if <fs_value> is assigned.
<fs_value> = "New number
endif.
endloop.
Hope this helps you.
Regards,
Rama