babel - python question

babel - python question

[Rustom Mody]

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[Complete babel noob here]

Following the babel doc
http://orgmode.org/worg/org-contrib/babel/intro.html#library-of-babel

I wrote this

* Head
#+name: ppp :results value
#+begin_src python
import time
print("Hello, today's date is %s" % time.ctime())
print('Two plus two is')
return 2 + 2
#+end_src

Hit C-c C-c

and got a new block

#+RESULTS:
: 4


I am mystified!
In python a top level return gives a syntax error.
Here it works. Is some secret function being created?

Also the results changed to output does not change the behavior

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Re: babel - python question

[Eric Schulte]

Rustom Mody <rustompmody@gmail.com> writes:

> [Complete babel noob here]
>
> Following the babel doc
> http://orgmode.org/worg/org-contrib/babel/intro.html#library-of-babel
>
> I wrote this
>
> * Head
> #+name: ppp :results value
> #+begin_src python
> import time
> print("Hello, today's date is %s" % time.ctime())
> print('Two plus two is')
> return 2 + 2
> #+end_src
>
> Hit C-c C-c
>
> and got a new block
>
> #+RESULTS:
> : 4
>
>
> I am mystified!
> In python a top level return gives a syntax error.
> Here it works. Is some secret function being created?
>

Yes, when returning a value, the code block itself becomes a function.

>
> Also the results changed to output does not change the behavior

Not true, however you need to put the header arguments on the begin_src
line or on a #+headers line (not on the #+name line).  Also, try to mix
:results output and "return 2 + 2", and you should find the error you
expected earlier.

Best,

#+begin_src python :results value
import time
print("Hello, today's date is %s" % time.ctime())
print('Two plus two is')
return 2 + 2
#+end_src

#+RESULTS:
: 4

#+begin_src python :results output
import time
print("Hello, today's date is %s" % time.ctime())
print('Two plus two is')
#+end_src

#+RESULTS:
: Hello, today's date is Fri Jul  5 08:27:02 2013
: Two plus two is

-- 
Eric Schulte
http://cs.unm.edu/~eschulte