Re: Re: dates in a spreadsheet

[Carsten Dominik <carsten.dominik@gmail.com>]

On Mar 17, 2010, at 11:39 PM, Bernt Hansen wrote:

> Josh Mattoon <joshmattoon@gmail.com> writes:
>
>> Hey Nick, the first one came through just fine. This is pretty cool  
>> but still not quite what I'm looking for.  It totally helped me get  
>> what I wanted though!  I wanted to have a separate row for each day
>> so I could fill in activities.  Modifying your example I get:
>>
>> | date             | place   | activity                  |  
>> notes            |
>> |------------------+---------+--------------------------- 
>> +------------------|
>> | <2010-03-19 Fri> |         |                           |  
>> dummy            |
>> | <2010-03-20 Sat> |         |                            
>> |                  |
>> | <2010-03-21 Sun> | moon    | collect rocks              
>> |                  |
>> | <2010-03-22 Mon> | jupiter | thrash around the red dot  
>> |                  |
>> | <2010-03-23 Tue> | mars    | see the little green men   
>> |                  |
>> | <2010-03-24 Wed> | earth   |                           | home,  
>> sweet home |
>> #+TBLFM: @2$1 = <03-19-2010>::$1 = @-1$1 + 1
>>
>> Exactly what I wanted!  I can insert days, move them around, and  
>> just hit C-u C-c C-c to have it update.  I'd like to understand how  
>> it works though, if you don't mind.  What does the ::$1 synax  
>> mean?  And
>> how did it know that we were dealing with a date?
>
> As I understand it
>
> This is a formula line with 2 formulas in it.  The formulas are
> separated by the ::
>
> @2$1 = <03-19-2010> sets the cell at row 2, column 1 to Mar 19, 2010
>
> Then the next formula just calculates all of the values for column 1
> leaving the static entry previously defined alone.
>
> $1 = @-1$1 + 1   column 1 entries are the previous row for column 1  
> plus 1
>
> so it just adds 1 to the initial value of the date for each following
> row in your table.

And the magic is that calc understands date and knows how to do
arithmetic with them.

- Carsten