Extract docstring form a python file using grep or awk

Question

I want to extract all docstrings from my python file using grep or awk. I tried

cat test.py | grep """[\w\W]*?"""

But I see no output. Say the the test test.py looks like this.

import libraries

class MyClass(object):
    """Docstring to this class. 
       second line of docstring."""

    def myClassMethod(a,b):
        """Docstring of the method. 
           another line in docstring of the method."""
        return a + b

Then the output should be all that is enclosed in triple quotes.

"""Docstring to this class. 
second line of docstring."""
"""Docstring of the method. 
another line in docstring of the method."""

We're gonna need more details, like input sample and expected output. — Paul-Etienne
– Paul-Etienne, Commented Oct 27, 2017 at 10:00

randomir · Accepted Answer · 2017-10-27 13:14:43Z

2

The proper way to extract docstrings from Python code is via actual Python parser (the ast module):

#!/usr/bin/env python
import ast

with open('/path/to/file') as f:
    code = ast.parse(f.read())

for node in ast.walk(code):
    if isinstance(node, (ast.FunctionDef, ast.ClassDef, ast.Module)):
        docstring = ast.get_docstring(node)
        if docstring:
            print(repr(docstring))

Run on your sample will output:

'Docstring to this class. \nsecond line of docstring.'
'Docstring of the method. \nanother line in docstring of the method.'

Just for fun, we can do also do it with GNU awk:

$ awk -v RS= -v FPAT="'''.*'''|"'""".*"""' '{print $1}' file
"""Docstring to this class. 
       second line of docstring."""
"""Docstring of the method. 
           another line in docstring of the method."""

edited Oct 27, 2017 at 13:14

answered Oct 27, 2017 at 12:44

randomir

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3 Comments

Piyush Divyanakar Over a year ago

I had found this method, but I was wondering if this could be done using grep or awk

randomir Over a year ago

I wouldn't recommend it over Python version, but take a look at the awk approach I just added.

Piyush Divyanakar Over a year ago

Thanks a lot this satisfied my curiosity

making_code · Accepted Answer · 2017-10-27 10:07:56Z

1

With P(perl) grep you can do the following:

grep -Poz '"""[^"]+"""' test.py

Output:

"""Docstring to this class. 
       second line of docstring.""""""Docstring of the method. 
           another line in docstring of the method."""

answered Oct 27, 2017 at 10:07

making_code

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2 Comments

Piyush Divyanakar Over a year ago

I am getting an error grep: unescaped ^ or $ not supported with -Pz

Piyush Divyanakar Over a year ago

Mine is grep (GNU grep) 2.24 if we use something other than perl regex does it work.

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