Reading in text data

[reardonb(at)my-deja.com]

Hi.  I am reading in text data (columns and rows of numbers) and I would
like to know if there is a more elegant way of doing it.  Currently, the
user must specify how many columns there are.  In my case the number of
columns is manually inserted into the first line of the file like this:

3
0 1 2
1 2 3
2 3 4
3 4 5
4 5 6
5 6 7
6 7 8
7 8 9
8 9 10
9 10 11

The attached procedure reads in the data.  Is there a way to read in the
data such that the user does not have to a priori know how many columns
there are and such that IDL does not have to reserve a large amount of
memory for the number of rows?
Thanks.
-Brian

;----------------------------------------------------------------

pro BG_File, event
compile_opt IDL2
@catch_procedure

widget_control, event.top, Get_Uvalue = pstate
IF XREGISTERED((*pstate).filename) GT 0 THEN RETURN

result = dialog_pickfile()
(*pstate).filename = result

columns = 0
max_rows = 30000
if (result) then begin
	OpenR, lun, result, /Get_lun
	Point_lun, lun, 0
	; Read in the number of data columns which should be
	; listed on the first line
	readf, lun, Columns
	temporary_data  = fltarr(columns,/nozero)
	temporary_array = fltarr(columns,max_rows,/nozero)
	counter = 0
	While (Not(EOF(lun)) and (counter lt max_rows)) Do Begin
		Readf, lun, temporary_data
		temporary_array[*,counter] = temporary_data
		counter = counter+1
		if counter eq max_rows then print, $
			'Sorry, too many rows in your data.'
	Endwhile
 	Free_lun, lun
	(*pstate).data =ptr_new(temporary_array[0:columns-1, $
		0:counter-1])
 endif

tlb    = widget_base (title=(*pstate).filename,/column, $
	/base_align_center,group_leader=event.top)
status = widget_label(tlb, value='',/dynamic_resize)
tdata   = widget_table(tlb,$
	group_leader=event.top, $
	/all_events,$
	/editable,$
	value=*((*pstate).data),$
	event_pro='BG_table_interactive',$
	x_scroll_size = columns,$
	y_scroll_size = 10)

table_struct = {status:status}
ptable_struct = ptr_new(table_struct, /no_copy)

widget_control, tlb, set_uvalue = ptable_struct
widget_control, tlb, /realize

xmanager, (*pstate).filename,tlb,cleanup='table_clean'

end
;----------------------------------------------------------------



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