Ipython code block producing org table

Question

I saw a python code block example to output an array as an org-table. An example would be,

#+BEGIN_SRC python :results value
  r = 3389.5 # km average radius
  re = 3396.2 # equatorial radius in km
  rp =  3376.2 # polar radius in km 
  m = 6.4171 * 10**(23) # kg

  return[["Parameter", "Value"],
   None,
   ["Mass Mars (kg)", "{:.5g}".format(m)],
   ["Mean Radius (km)", "{:.5g}".format(r)],
   ["Polar Radius (km)", "{:.5g}".format(rp)],
   ["Equatorial Radius (km)", "{:.5g}".format(re)]]

#+END_SRC

#+RESULTS:
| Parameter              |      Value |
|------------------------+------------|
| Mass Mars (kg)         | 6.4171e+23 |
| Mean Radius (km)       |     3389.5 |
| Polar Radius (km)      |     3376.2 |
| Equatorial Radius (km) |     3396.2 |

This is almost perfect for me. I would like to be able to use ipython in session mode in order to pull results from various other code blocks without naming them individually with :var headers.

However, with ipython I get the error:

SyntaxError: 'return' outside function

I'm not sure why there is this difference in behavior between python and ipython code blocks. If I remove "return" from the ipython code block, I get the following output (no table):

#+BEGIN_SRC ipython :session mars :results value
   [["Parameter", "Value"],
   ["Mass Mars (kg)", "{:.5g}".format(m)],
   ["Mean Radius (km)", "{:.5g}".format(r)],
   ["Polar Radius (km)", "{:.5g}".format(rp)],
   ["Equatorial Radius (km)", "{:.5g}".format(re)]]

#+END_SRC

#+RESULTS:
:RESULTS:
# Out[109]:
# text/plain
: [['Parameter', 'Value'],
:  ['Mass Mars (kg)', '6.4171e+23'],
:  ['Mean Radius (km)', '3389.5'],
:  ['Polar Radius (km)', '3376.2'],
:  ['Equatorial Radius (km)', '3396.2']]
:END:

Using the header argument ":results value table" doesn't work either:

 #+BEGIN_SRC ipython :session mars :results value table
       [["Parameter", "Value"],
       ["Mass Mars (kg)", "{:.5g}".format(m)],
       ["Mean Radius (km)", "{:.5g}".format(r)],
       ["Polar Radius (km)", "{:.5g}".format(rp)],
       ["Equatorial Radius (km)", "{:.5g}".format(re)]]

    #+END_SRC

    #+RESULTS:
    :RESULTS:
    | # Out[1]: |
    :END:

In this case, is the best option just to do something like following? Am I missing a better solution? My end use scenario is exporting the org-file to pdf with a mixture of latex formulas as well as ipython code blocks and text.

#+BEGIN_SRC ipython :session mars 

print("|-")
print("| Parameter | Value |")
print("|-")
print(f"|Mass Mars (kg) | {m}|")
print(f"|Mean Radius (km) | {r}|")
print(f"|Polar Radius (km) | {rp}|")
print(f"|Equatorial Radius (km) | {re}|")
print(f"|-")
print("#+TBLFM: $2=$0;%0.5g")
#+END_SRC

#+RESULTS:
:RESULTS:
# Out[116]:
# output
|------------------------+------------|
| Parameter              |      Value |
|------------------------+------------|
| Mass Mars (kg)         | 6.4171e+23 |
| Mean Radius (km)       |     3389.5 |
| Polar Radius (km)      |     3376.2 |
| Equatorial Radius (km) |     3396.2 |
|------------------------+------------|
#+TBLFM: $2=$0;%0.5g

Answer 1

You don't need to format things as tables to pass information between blocks with ipython in scimax; each block is "connected" via the kernel that is running in the background, so variables created in one block are available in another block. You might still want to output a table of results for easy reading, and a nice way to do this is with the tabulate package.

You can make a table like this:

#+BEGIN_SRC ipython
import tabulate

r = 3389.5 # km average radius
re = 3396.2 # equatorial radius in km
rp =  3376.2 # polar radius in km
m = 6.4171 * 10**(23) # kg

print(tabulate.tabulate([["Mass Mars (kg)", "{:.5g}".format(m)],
                         ["Mean Radius (km)", "{:.5g}".format(r)],
                         ["Polar Radius (km)", "{:.5g}".format(rp)],
                         ["Equatorial Radius (km)", "{:.5g}".format(re)]],
                        ["Parameter", "Value"],
                        tablefmt='orgtbl'))
#+END_SRC

#+RESULTS:
:results:
# Out [8]:
# output
| Parameter              |      Value |
|------------------------+------------|
| Mass Mars (kg)         | 6.4171e+23 |
| Mean Radius (km)       |     3389.5 |
| Polar Radius (km)      |     3376.2 |
| Equatorial Radius (km) |     3396.2 |

:end:

Later in a new cell you can reuse one of the previously defined variables like this:

#+BEGIN_SRC ipython
m
#+END_SRC

#+RESULTS:
:results:
# Out [9]: 
# text/plain
: 6.417099999999999e+23
:end:

Each buffer has its own automatic session in scimax, so I don't recommend you use the :session header argument without some good reason.

Answer 2

[Not a complete answer, but too long for a comment.]

The main problem above is that session and non-session evaluation of python code blocks is different: in non-session, the code block is wrapped in a phantom function, hence the return makes sense; but no such thing happens in session evaluation. You will probably be better off changing the header args to :results output table :session mars and then changing the code block to print the value, rather than return it:

#+BEGIN_SRC python :results output table :session mars
  r = 3389.5 # km average radius
  re = 3396.2 # equatorial radius in km
  rp =  3376.2 # polar radius in km 
  m = 6.4171 * 10**(23) # kg

  print([["Parameter", "Value"],
   None,
   ["Mass Mars (kg)", "{:.5g}".format(m)],
   ["Mean Radius (km)", "{:.5g}".format(r)],
   ["Polar Radius (km)", "{:.5g}".format(rp)],
   ["Equatorial Radius (km)", "{:.5g}".format(re)]])

#+END_SRC

This does not address the ipython question at all, because I don't know enough about it to offer any useful advice. What I do know is that, by default, org-mode does not provide an ob-ipython implementation, so you must have installed something extra to get ipython code blocks to "work" (for some value of "work": in my case, if I change the source language tag to ipython in my setup, I get an error: No org-babel-execute function for ipython!).