Python notebook use return value from running a script

Question

I am using a notebook (in Google Colab) in python 3 and really need to execute some python2 code with some data that is generated in my notebook !

So what I did was

Generate the data in my cells AND save it to a file (data.txt)
Write a python 2 script (myScript.py) with a main() function that parses the file from sys.argv[1] into data and than calls my python2 functions and do all the stuff then it ends with return results (which is a dictionary)
In my notebook I run

!python2 myScript.py ./data.txt

(They are of course all in the same directory)

The command runs with no errors but no output ! How do I catch the results that are returned in a variable that I could use later ?

Not important but could be helpful :

Is there a better way to actually achieve what I am willing to achieve ?

On possibility would be to make your python script write to stdout and read it back as a string: myvar = !python2 myScript.py ./data.txt myScript.py should write to stdout using print or similar. ` def main(): print('Hello World') ` If you have a dictionary, you could either use eval() or print it csv like and parse back to a dict — Manuel
– Manuel, Commented Jun 16, 2020 at 13:30
Thank you for your answer, I didn't know we could do myvar = !python2 myScript.py ./data.txt, I used that insight to dump my dictionary as JSON then loading it from my notebook. Thank you for your help — Fayçal Borsali
– Fayçal Borsali, Commented Jun 16, 2020 at 14:50

Fayçal Borsali · Accepted Answer · 2020-06-16 14:55:18Z

1

Thanks to @Manuel's comment on the question, I figured out this solution and it worked :

In myScript.py, I changed return results by sys.stdout.write(json.dumps(results))
In my notebook, I changed the cell that executes the script to this:

results = !python2 test_langdetect.py ./tmp_comments.txt
myVar = json.loads(results[0])

Of course you need to import json

answered Jun 16, 2020 at 14:55

Fayçal Borsali

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