Re: Org Babel says 1 + 1 in Python is None

[Sébastien Gendre]

But, 1 + 1 should be 11.

Joke aside, for Python, how you return the value depend of if you use a
session or not.

By default, a Python code block do not use a session. In this case, when
executed, the code is wrapped into a Python function and then this
function is called. So, to return a value, you need to use the "return"
statement.

With your example:
  src_python{return 1 + 1}


When you use a session for your code block, the last statement value is
returned if it is a top level expression. In this case, you do not use a
"return" statement.



Is it the article you have read on WORG ?
https://orgmode.org/worg/org-contrib/babel/languages/ob-doc-python.html

The part you have quoted maybe miss a reference to the section who
explain how the return mechanism work for values.


Best regards

-------
Gendre Sébastien


Rudolf Adamkovič <rudolf@adamkovic.org> writes:

> Today, I decided to start using Python in Org.
>
> (1) I read in "WORG":
>
>   :results {output, value}: [...] Value results are the value of the
>   last expression evaluated in the code block. Value mode is the default
>   (as with other languages).
>
> (2) So, I try it, and get:
>
>   src_python{1 + 1} {{{results(=None=)}}}
>
> I expected this to be 2.
>
> Questions:
>
> - Who is correct: (1) the documentation or (2) the implementation?
> - If (2) is correct, do I have to write `return' every time?
>
> Rudy

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