How to skip the docstring using regex

Question

I'm trying to insert some import lines into a python source file, but i would ideally like to place them right after the initial docstring. Let's say I load the file into the lines variable like this:

lines = open('filename.py').readlines()

How to find the line number, where the docstring ends?

Answer 1

If you're using the standard docstring format, you can do something like this:

count = 0
for line in lines:
    if line.startswith ('"""'):
        count += 1
        if count < 3:
            # Before or during end of the docstring
            continue
    # Line is after docstring

Might need some adaptation for files with no docstrings, but if your files are formatted consistently it should be easy enough.

Answer 2

Actually I was looking for the index, but that helped me to find the correct solution. Thanks

Answer 3

Rather than using a regex, or relying on specific formatting you could use python's tokenize module.

import tokenize
f=open(filename)
insert_index = None
for tok, text, (srow, scol), (erow,ecol), l in tokenize.generate_tokens(f.readline):
    if tok == tokenize.COMMENT:
        continue
    elif tok == tokenize.STRING:
        insert_index = erow, ecol
        break
    else:
        break # No docstring found

This way you can even handle pathological cases like:

# Comment
# """Not the real docstring"""
' this is the module\'s \
docstring, containing:\
""" and having code on the same line following it:'; this_is_code=42

excactly as python would handle them.