Split a big text file into multiple smaller one on set parameter of regex - python-3.x

Question

I have a large text file looking like:
....
sdsdsd
..........
asdfhjgjksdfk dfkaskk sdkfk skddkf skdf sdk ssaaa akskdf sdksdfsdf ksdf sd kkkkallwow.
sdsdllla lsldlsd lsldlalllLlsdd asdd. sdlsllall asdsdlallOEFOOASllsdl lsdlla.
slldlllasdlsd.ss;sdsdasdas.
......
ddss
................
asdfhjgjksdfk ddjafjijjjj.dfsdfsdfsdfsi dfodoof ooosdfow oaosofoodf aosolflldlfl , dskdkkfkdsa asddf;akkdfkdkk . sdlsllall asdsdlallOEFOOASllsdl lsdlla.
slldlllasdlsd.ss;sdsdasdas.
.....
xxxx
.......
asdfghjkl
I want to split the text files into multiple small text files and save them as .txt in my system on occurences of ..... [multiple period markers] saved like
group1_sdsdsd.txt
....
sdsdsd
..........
asdfhjgjksdfk dfkaskk sdkfk skddkf skdf sdk ssaaa akskdf sdksdfsdf ksdf sd kkkkallwow.
sdsdllla lsldlsd lsldlalllLlsdd asdd. sdlsllall asdsdlallOEFOOASllsdl lsdlla.
slldlllasdlsd.ss;sdsdasdas.
group1_ddss.txt
ddss
................
asdfhjgjksdfk ddjafjijjjj.dfsdfsdfsdfsi dfodoof ooosdfow oaosofoodf aosolflldlfl , dskdkkfkdsa asddf;akkdfkdkk . sdlsllall asdsdlallOEFOOASllsdl lsdlla.
slldlllasdlsd.ss;sdsdasdas.
and
group1_xxxx.txt
.....
xxxx
.......
asdfghjkl
I have figured that by usinf regex of sort of following can be done
txt =re.sub(r'(([^\w\s])\2+)', r' ', txt).strip() #for letters more than 2 times
but not able to figure out completely.
The saved text files should be named as group1_sdsdsd.txt , group1_ddss.txt and group1_xxxx.txt [group1 being identifier for the specific big text file as I have multiple bigger text files and need to do same on all to know which big text file i am splitting.

Answer 1

If you want to get the parts with multiple dots only on the same line, you can use and get the separate parts, you might use a pattern like:
^\.{3,}\n(\S+)\n\.{3,}(?:\n(?!\.{3,}\n\S+\n\.{3,}).*)*
Explanation
^ Start of string
\.{3,}\n Match 3 or more dots and a newline
(\S+)\n Capture 1+ non whitespace chars in group 1 for the filename and match a newline
\.{3,} Match 3 or more dots
(?: Non capture group to repeat as a whole part
\n Match a newline
(?!\.{3,}\n\S+\n\.{3,}) Negative lookahead, assert that from the current position we are not looking at a pattern that matches the dots with a filename in between
.* Match the whole line
)* Close the non capture group and optionally repeat it
Then you can use re.finditer to loop the matches, and use the group 1 value as part of the filename.
See a regex demo and a Python demo with the separate parts.
Example code
import re
pattern = r"^\.{3,}\n(\S+)\n\.{3,}(?:\n(?!\.{3,}\n\S+\n\.{3,}).*)*"
s = ("....your data here")
matches = re.finditer(pattern, s, re.MULTILINE)
your_path = "/your/path/"
for matchNum, match in enumerate(matches, start=1):
f = open(your_path + "group1_{}".format(match.group(1)), 'w')
f.write(match.group())
f.close()