Re: Table filter.

[Nick Dokos <nicholas.dokos@hp.com>]

Bastien <bzg@gnu.org> wrote:

> Hi Petro,
> 
> Petro  <x.piter@gmail.com> writes:
> 
> > lets say I have a table
> >
> > | n | 2 | 3 | 4 | 5 | 6 |
> > |---+---+---+---+---+---|
> > | 1 | a |   |   |   |   |
> > | 2 | b |   |   |   |   |
> > | 3 | b |   |   |   |   |
> > | 4 | a |   |   |   |   |
> > | 5 | c |   |   |   |   |
> > | 6 | b |   |   |   |   |
> > | 7 | a |   |   |   |   |
> >
> > I want to filter this table and get only rows where second column equal a
> > | n | 2 | 3 | 4 | 5 | 6 |
> > |---+---+---+---+---+---|
> > | 1 | a |   |   |   |   |
> > | 4 | a |   |   |   |   |
> > | 7 | a |   |   |   |   |
> 
> Such feature does not exist for now, but I would welcome enhancements in
> this direction.  Thanks for this idea,
> 

You can get most of the way there with babel, as long as you don't insist
on modifying the table in place. Something like this e.g. using python 2.x:

--8<---------------cut here---------------start------------->8---
#+BEGIN_SRC elisp
(setq org-babel-min-lines-for-block-output 0)
#+END_SRC

#+RESULTS:
#+begin_example
0
#+end_example

The above setting is just to force an example block. The default value
(10) produces colon-demarcated results.


#+name: orig
| n | 2 | 3 | 4 | 5 | 6 |
|---+---+---+---+---+---|
| 1 | a |   |   |   |   |
| 2 | b |   |   |   |   |
| 3 | b |   |   |   |   |
| 4 | a |   |   |   |   |
| 5 | c |   |   |   |   |
| 6 | b |   |   |   |   |
| 7 | a |   |   |   |   |

#+BEGIN_SRC python :var table=orig :results output
  # print the header
  print "#+name: filtered"
  for x in table:
      if x[1] == 'a':
          print "|%s" % ("|".join(map(str, x)))
#+END_SRC

#+RESULTS:
#+begin_example
#+name: filtered
|1|a||||
|4|a||||
|7|a||||
#+end_example
--8<---------------cut here---------------end--------------->8---

I don't know how to get the column heading row though: apparently babel
strips it from the table it passes to the code block.

Nick