Extracting text from plain HTML and write to new file - html

Question

I'm extracting a certain part of a HTML document (to be fair: basis for this is an iXBRL document which means I do have a lot of written formatting code inside) and write my output, the original file without the extracted part, to a .txt file. My aim is to measure the difference in document size (how much KB of the original document refers to the extracted part). As far as I know there shouldn't be any difference in HTML to text format, so my difference should be reliable although I am comparing two different document formats. My code so far is:
import glob
import os
import contextlib
import re
#contextlib.contextmanager
def stdout2file(fname):
import sys
f = open(fname, 'w')
sys.stdout = f
yield
sys.stdout = sys.__stdout__
f.close()
def extractor():
os.chdir(r"F:\Test")
with stdout2file("FileShortened.txt"):
for file in glob.iglob('*.html', recursive=True):
with open(file) as f:
contents = f.read()
extract = re.compile(r'(This is the beginning of).*?Until the End', re.I | re.S)
cut = extract.sub('', contents)
print(file.split(os.path.sep)[-1], end="| ")
print(cut, end="\n")
extractor()
Note: I am NOT using BS4 or lxml because I am not only interested in HTML text but actually in ALL lines between my start and end-RegEx incl. all formatting code lines.
My code is working without problems, however as I have a lot of files my FileShortened.txt document is quickly going to be massive in size. My problem is not with the file or the extraction, but with redirecting my output to various txt-file. For now, I am getting everything into one file, what I would need is some kind of a "for each file searched, create new txt-file with the same name as the original document" condition (arcpy module?!)?
Somehting like:
File1.html --> File1Short.txt
File2.html --> File2Short.txt
...
Is there an easy way (without changing my code too much) to invert my code in the sense of printing the "RegEx Match" to a new .txt file instead of "everything except my RegEx match"?
Any help appreciated!

Answer 1

Ok, I figured it out.
Final Code is:
import glob
import os
import re
from os import path
def extractor():
os.chdir(r"F:\Test") # the directory containing my html
for file in glob.glob("*.html"): # iterates over all files in the directory ending in .html
with open(file) as f, open((file.rsplit(".", 1)[0]) + ".txt", "w") as out:
contents = f.read()
extract = re.compile(r'Start.*?End', re.I | re.S)
cut = extract.sub('', contents)
out.write(cut)
out.close()
extractor()