+- Python Forum (https://python-forum.io)
+-- Forum: Python Coding (https://python-forum.io/forum-7.html)
+--- Forum: Web Scraping & Web Development (https://python-forum.io/forum-13.html)
+--- Thread: How do I extract specific lines from HTML files before and after a word? (/thread-20334.html)
How do I extract specific lines from HTML files before and after a word? - glittergirl - Aug-05-2019
I am trying to extract the 10 lines before and after the word "apple" from a directory (with subdirectories) full of HTML files. I want to print out the lines into a CSV file. Ideally, the CSV file will contain two variables: 1) the HTML filename and 2) the 10 lines before and after the word "apple".
I have done the following:
import glob
import collections
import itertools
import sys
import csv
for filepath in glob.glob('**/*.html', recursive=True):
with open(filepath) as f:
before = collections.deque(maxlen=10)
for line in f:
if 'apple' in line:
sys.stdout.writelines(before)
sys.stdout.write(line)
sys.stdout.writelines(itertools.islice(f, 10))
break
results = before.append(line)
print(results)I am currently getting a bunch of rows that say "None" in my terminal when I print the results. What is the issue here?
RE: How do I extract specific lines from HTML files before and after a word? - fishhook - Aug-06-2019
Why do you expect that "append" method returns a value?
https://docs.python.org/2/library/collections.html#collections.deque.append
Nothing about the value returned. In case if a function doesn't return a result python always returns None.