Doubts regarding space separated ASCII files

[Mark Taylor]

On Mon, 4 Dec 2006, Prameela Nair wrote:

> We are trying to modify the implementation for VOConvert
> (http://vo.iucaa.ernet.in/~voi/VOConvert.htm) which is a tool to convert
> ASCII/FITS file(s) to the VOTable format.
>
>
>
> Some queries regarding space separated ASCII files -
>
>
>
> 1) How are null values represented? Do we add an additional space to
> represent a null value for the column?
>
>
>
> 2) Are there space separated ASCII files where the number of spaces that
> separate two values/columns is greater than 1?
>
>   e.g. - here values for columns are separated by 2 spaces
>
>   12  345  67  2345
>
>   1235  234  1  265
>
>
>
>
>
> For the fixed format files -
>
> 1) Do null values exist in fixed format files? If yes, how are they
> represented?

Dear Prameela,

there is no single widely-used formal or informal standard for the 
format of space-separated or fixed-format ASCII files used to 
represent tables.  Everyone just writes them the way that seems most 
obvious to them or that happens to suit the programming languages or 
tools that they have available.  They then may or (more usually) 
may not publish an explicit description of the rules which they 
have used.  This makes it more or less impossible to write a 
one-size-fits-all ASCII->FITS translator.  So the answers to your 
questions depend on whose ASCII tables you are talking about.
However, for this one:

> 2) Are there space separated ASCII files where the number of spaces that
> separate two values/columns is greater than 1?

I'd say that in most cases one space character is to be interpreted
the same way as multiple space characters, so usually the answer is yes.

Mark

-- 
Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
m.b.taylor at bris.ac.uk +44-117-928-8776 http://www.star.bris.ac.uk/~mbt/