replacing line in a document with Python

Question

I have the following file and I would like to replace #sys.path.insert(0, os.path.abspath('.')) with sys.path.extend(['path1', 'path2'])

import sys
import os

# If extensions (or modules to document with autodoc) are in another directory,
# add these directories to sys.path here. If the directory is relative to the
# documentation root, use os.path.abspath to make it absolute, like shown here.
#sys.path.insert(0, os.path.abspath('.'))

# -- General configuration ------------------------------------------------

However, the following code does not change the line.

with open(os.path.join(conf_py_path, "conf.py"), 'r+') as cnfpy:
    for line in cnfpy:
        line.replace("#sys.path.insert(0, os.path.abspath('.')))",
                    "sys.path.extend(%s)\n" %src_paths)
        cnfpy.write(line)

How is it possible to replace the line?

http://stackoverflow.com/questions/9189172/python-string-replace — , Sep 20 '14 at 08:17
the problem can be demonstrated without opening a file. please strive to create a minimal example. — Karoly Horvath, Sep 20 '14 at 08:19
We have two problems here: 1. Not saving the result of `line.replace()`, 2. Not reading and writing a file opened in `r+` mode correctly. — PM 2Ring, Sep 20 '14 at 13:39

Edmond Burnett · Accepted Answer · 2014-09-20T16:56:13.313

1

Try fileinput to change a string in-place within a file:

import fileinput
for line in fileinput.input(filename, inplace=True):
    print(line.replace(string_to_replace, new_string))

edited Sep 20 '14 at 16:56

answered Sep 20 '14 at 08:26

Edmond Burnett

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Thank you, I had to do *print line.replace(...,...),* – user977828 Sep 20 '14 at 10:06
@user977828, right. I've edited the answer. – Edmond Burnett Sep 20 '14 at 16:57

replacing line in a document with Python

1 Answers1