Python, Org Mode, and writing Org tables to CSVs so that I can read them back

Sacha Chua — Sun, 27 Oct 2019 16:08:00 GMT

I’ve been getting deeper into Python so that I can model our personal finances. I really like using the pandas library to manipulate data. All those years I spent trying to juggle increasing complex spreadsheets… Working with Python code in Org Babel blocks is just so much more fun. I like being able to keep my assumptions in tables without having to fuss around with naming cells for easy-to-read formulas, slice and summarize parts of my data frames, organize my notes in outlines and add commentary, and define more complicated functions that I don’t have to squeeze into a single line.

I haven’t quite been able to tempt W- into the world of Org Babel Python blocks. Still, I don’t want to give up the awesomeness of having pretty tables that I can easily edit and use. So I have a bunch of named tables (using #+NAME:), and some code that exports my tables to CSVs:

#+NAME: tables
| Table         | Key                 |
|---------------+---------------------|
| assets_w      | Description         |
| assets_s      | Description         |
| tax_rates     |                     |
| disposition   | Asset               |
| probate_rates | Asset               |
| basic         | Client information  |
| base_expenses | Category            |
| general       | General assumptions |

#+begin_src emacs-lisp :results silent :var tables=tables :tangle no
  (defun my-tbl-export (row)
    "Search for table named `NAME` and export."
    (interactive "s")
    (save-excursion
      (goto-char (point-min))
      (let ((case-fold-search t))
        (when (search-forward-regexp (concat "#\\+NAME: +" (car row)) nil t)
          (next-line)
          (org-table-export (format "%s.csv" (car row)) "orgtbl-to-csv")))))
  (mapc 'my-tbl-export tables)
#+end_src

and some code that imports them back in, and formats tables nicely if I’m displaying them in Org. The in_org block doesn’t get tangled into index.py, so I don’t clutter command-line use with Org table markup.

#+begin_src python :results silent :tangle no
  in_org=1
#+end_src

#+begin_src python :results silent :exports code
  import pandas as pd
  import numpy as np
  import orgbabelhelper as ob
  def out(df, **kwargs):
    if 'in_org' in globals():
      print(ob.dataframe_to_orgtable(df, **kwargs))
    else:
      print(df)
    return df
#+end_src

#+begin_src python :results silent :var tables=tables :colnames yes
  for row in tables:
    table = row[0]
    index = row[1] 
    if row[1] == '':
      index = None
    globals()[table] = pd.read_csv(table + '.csv', index_col=index).apply(pd.to_numeric, errors='ignore')
    # print(globals()[table])
#+end_src

Then I can use C-c C-v C-b (org-babel-execute-buffer) to update everything if I change the table in my Org file, and I can use C-c C-v C-t (org-babel-tangle) to create an index.py that W- can read through or run without needing Org.

Sacha Chua - category - babel

Python, Org Mode, and writing Org tables to CSVs so that I can read them back