Re: [O] noweb and :var statements

[Sebastian Miele]

Ken Mankoff <address@hidden> writes:

> Hi Sebastian,
>
> I'm not getting the results I expect from your MWE either. Perhaps I
> gave too much code and asked X when what I really want is Y. I think
> I've distilled it to this:
>
> What is the most elegant Org way to get a table into a Python array?

I do not know whether it is the most elegant way, but the following
works, and probably is at least close to shortes possible way:

#+NAME: table_foo
| foo |
|-----|
|  42 |
| 100 |

#+BEGIN_SRC python :var table=table_foo :tangle table.py
#+END_SRC

After tangling, table.py contains "table=[[42], [100]]".

Did you know that you can have several source code blocks tangling to
the same file? Maybe you do not really need noweb stuff at all. If you
add a second block, e.g.

#+BEGIN_SRC python :tangle table.py
mangle_table
#+END_SRC

then, after tangling, table.py contains "table=[[42], [100]]" and
"mangle_table".


> I can code it directly:
>
> #+BEGIN_SRC python
> <<setup>>
> print(foo)
> #+END_SRC
>
>
> And now I can hide <<setup>> in a section at the bottom of the
> document. If it looks like this, everything works:
>
> #+NAME: setup
> #+BEGIN_SRC python
> foo = np.array([42,43,44])
> #+END_SRC
>
> But is there a more elegant method? Can I get the same behavior if the
> data I want is in an Org table rather than hard-coded directly in
> Python?

This use-case is covered by what I wrote above. You can put the named
Org table at the bottom of the file.

Another note: You can tangle to different files from one Org file. You
may e.g. add an additional source block:

#+BEGIN_SRC python :tangle use_table.py
include_table_py
use_table
#+END_SRC

where include_table_py must be replaced by the Python way of saying:
include the file table.py. (I do not know Python.)

> Ideally, I'd like to have:
>
> #+NAME: setup
> #+BEGIN_SRC python
> <<setup(table="foo_data" varname="foo")>>
> <<setup(table="bar_data" varname="bar")>>
> #+END_SRC
>
> And a #+NAME: setup block that takes a :var table and sticks it in the
> :var varname variable.

I strongly suspect that you do not really need noweb stuff and still
struggle to understand the very basics of tangling.

> And then after calling <<setup>> be able to use variable "foo" and
> "bar" that are generated from column or 2D Org tables elsewhere in the
> document. Can I do this in Org?
>
> Thanks,
>
>   -k.