Re: Writing to ASCII files

[Ivan Zimine <ivan.zimine(at)physics.unige.ch>]

Jasmeet Judge wrote:
> 
> Hi,
>         I just started reading this newsgroup. I found out
> about its existence after 6 yrs of IDL-use on UNIX!! I never
> could write an ascii file with columns of no.s from IDL.
> I have two specific qs. regarding this:
> 
> 1. When I use printf (and even writeu), it gives me
> non-sensible results. Here is what I am doing
> 
> openw,unitno,filename
> some loop with i
> printf,unitno,item1(i),item2(i)
> end loop
> close,unitno
> 
> What I would like is:
> item1(0) item2(0)
> item1(1) item2(1)
> item1(2) item2(2)
> item1(3) item2(3)
> 
> Instead, I get some unreadable jargon (I guess it is writing
> binary?). Is there a way to do this in IDL?
> 
> 2. Is there a way to open a file to write (with openw) but have
> it keep appending data at the end of file with every call to printf?
> 


IDL> print, !version
{ x86 linux unix 5.2.1L Aug  2 1999}

IDL> x=indgen(10)
IDL> y = x*2
IDL> openw, lun, 'test.txt', /get_lun
IDL> for i=0,9 do printf, lun, x[i], y[i], format='(i4, i4)'
IDL> free_lun, lun

IDL> openw, 1, 'test.txt', /append
IDL> for i=0,9 do printf, 1, x[i]+10, y[i]*2, format='(i4, i4)'
IDL> close,1

prompt% cat test.txt
   0   0
   1   2
   2   4
   3   6
   4   8
   5  10
   6  12
   7  14
   8  16
   9  18
  10   0
  11   4
  12   8
  13  12
  14  16
  15  20
  16  24
  17  28
  18  32
  19  36

regards,
Ivan

-- 
Ivan Zimine                   |   ivan.zimine@physics.unige.ch
Dpt. of Radiology             |   (+41 22) 372 70 70
Geneva University Hospitals   |