Re: Computations on properties

[Eric Abrahamsen <eric@ericabrahamsen.net>]

Eric Schulte <schulte.eric@gmail.com> writes:

> Thorsten Jolitz <tjolitz@gmail.com> writes:
>
>> Eric Abrahamsen <eric@ericabrahamsen.net> writes:
>>
>>> Thierry Pellé <thierry.pelle@soliavos.fr> writes:
>>>
>>>> Hi,
>>>>   I'm seeking how to do something like that
>>>>
>>>> Let the following text inserted in an org-mode file
>>>>
>>>> * Mean Calculation
>>>>  :PROPERTIES:
>>>>  :VAL1: 5
>>>>  :VAL2: 10
>>>>  :COEF: 10
>>>>  :END:
>>>>
>>>> I would like to append the result of a computation 
>>>> like RES=(VAL1*COEF+VAL2)/(COEF+1) 
>>>>
>>>> Something like 
>>>> * Mean Calculation
>>>> ...
>>>>   :END:
>>>>
>>>> Mean Calculation=RES (where RES is the value of the result)
>>>>
>>>> I think to do this with a python script but is there a more org-mode/emacs
>>>> method to do it?
>>>
>>> Sometimes I think it would be nice to have a way to draw property values
>>> directly into a babel block, the way you can with table data. Sort of
>>> like:
>>>
>>> * Heading
>>>   :PROPERTIES:
>>>   :ID:       3f78f08a-ccca-4fc0-aba9-2a192f7a0e5a
>>>   :foo:  5
>>>   :bar:  puppy
>>>   :END:
>>>
>>> #+BEGIN_SRC emacs-lisp :var alist=3f78f08a-ccca-4fc0-aba9-2a192f7a0e5a
>>>
>>> And in the block, the "alist" variable would look like '(:foo 5 :bar
>>> "puppy").
>>>
>>> What would be even better would be to run a tags search on matching
>>> headlines and feed all property drawers into a single block, as a list
>>> of alists. Just thinking out loud...
>>
>> This is probably not really what you want, but at least somehow related. I
>> would not know how to do this via source-block arguments, but maybe you can
>> use the results of one source-block (that produces the data) as input for
>> another source-block that does the real work. 
>>
>> * Heading 1 :match:
>>   :PROPERTIES:
>>   :ID:       3f78f08a-ccca-4fc0-aba9-2a192f7a0e5a
>>   :foo:  5
>>   :bar:  puppy
>>   :END:
>>
>> * Heading 2
>>   :PROPERTIES:
>>   :ID:       3f78f08a-ccca-4fc0-aba9-2a192f7a0e5b
>>   :foo:  6
>>   :bar: yuppy
>>   :END:
>>
>>
>> * Heading 3 :match:
>>   :PROPERTIES:
>>   :ID:       3f78f08a-ccca-4fc0-aba9-2a192f7a0e5c
>>   :foo:  7
>>   :bar:  hippie
>>   :END:
>>
>>
>> #+begin_src emacs-lisp :results raw
>>    (let ((lst))
>>       (org-map-entries
>>        (lambda () (cons (org-entry-properties) lst))
>>        "match" 'file))
>> #+end_src
>>
>> #+results:
>> ((((FILE . /home/tj/News/drafts/drafts/419) (TAGS . :match:) (ALLTAGS
>> . :match:) (BLOCKED . ) (ID . 3f78f08a-ccca-4fc0-aba9-2a192f7a0e5a) (foo . 5)
>> (bar . puppy) (CATEGORY . 419))) (((FILE . /home/tj/News/drafts/drafts/419)
>> (TAGS . :match:) (ALLTAGS . :match:) (BLOCKED . ) (ID .
>> 3f78f08a-ccca-4fc0-aba9-2a192f7a0e5c) (foo . 7) (bar . hippie) (CATEGORY .
>> 419))))
>
> Or maybe something like the following...
>
> * Mean Calculation
>  :PROPERTIES:
>  :VAL1: 5
>  :VAL2: 10
>  :COEF: 10
>  :END:
>
> #+begin_src python :var props=(mapcar (lambda (p) (list (car p) (cdr p))) (org-entry-properties))
>   return props
> #+end_src

This is very cool! Thanks.

> #+RESULTS:
> | FILE     | /tmp/property-computation.org |
> | BLOCKED  |                               |
> | VAL1     |                             5 |
> | VAL2     |                            10 |
> | COEF     |                            10 |
> | CATEGORY |          property-computation |