2014-06-01 12:58 GMT+02:00 Michael Brand <michael.ch.brand@gmail.com>:

> On Sun, Jun 1, 2014 at 12:00 PM, Cecil Westerhof <cldwesterhof@gmail.com>
> wrote:
> > 2014-06-01 11:50 GMT+02:00 Cecil Westerhof <cldwesterhof@gmail.com>:
> >> I am trying the following:
> >>     #+TBLFM: @-I$4..@+I$4 = if("$3" == "nan", string(""), $3 - $2) ;
> %.1f
> >> and:
> >>     #+TBLFM: @-I$4..@+I$4 = if("$3" == "", string(""), $3 - $2) ; %.1f
> >>
> >> But in both case the fourth field is filled when the third field is
> empty.
> >> What am I doing wrong?
> >>
> >> I am using version 8.2.1.
> >
> > The following does work:
> >     #+TBLFM: @-I$4..@+I$4 = if($3 - $2 == -$2, string(""), $3 - $2) ;
> >
> > But is not what is described.
> >
> > I removed
> >     %.1f
> > because that displays an empty string as 0.0.
> >
> > Is it possible to use %.1f without making an empty field displayed as
> 0.0?
>
> I suggest that I will improve the TBLFM example about "nan" in the
> manual like this:
>
>     `if("$1" == "nan" || "$2" == "nan", string(""), $1 + $2); E f-1'
>          Sum of the first two columns.  When at least one of the input
>          fields is empty the Org table result field is set to empty.  `E'
>          is required to leave empty fields without conversion to 0.  `f-1'
>          is an optional Calc format string similar to `%.1f' but leaves
>          empty results empty.
>
> Would this have answered all your questions?
>

​That does what I want. Thanks.

-- 
Cecil Westerhof