Python regex to replace a Particular line in paragraphs as per regex only not whole file

Question

s="""Paragraph 1
some text blah blah
blah blah
UNWANTED TEXT
some text
Paragraph END

UNWNTED TEXT

Paragraph 2
some text blah blah
blah blah
UNWNTED TEXT
Paragraph END"""

Now python code to re.sub to replace UNWANTED TEXT only inside paragraphs keep UNWANTED TEXT Outside paragraphs

search_unwanted_only_inparagrap = re.findall('(?s)(?<=Paragraph)(.*?)(?=END)', text_file, flags = re.MULTILINE )
if search_unwanted_only_inparagrap:
    replace_only_insidepara = re.sub(r"UNWANTED TEXT+", " ", text_file)   #replace string substitue
    print (replace_only_insidepara)
else:
    print ("not found")    

But the output replace all instance of UNWANTED TEXT in through out the file

Paragraph 1
some text blah blah
blah blah

some text
Paragraph END



Paragraph 2
some text blah blah
blah blah

Paragraph END

but i expect like this

Paragraph 1
some text blah blah
blah blah

some text
Paragraph END

UNWNTED TEXT

Paragraph 2
some text blah blah
blah blah

Paragraph END

Please help.

Answer 1

Your demo input should have been more 'minimal'. However, I tried to understand your requirement and I tried re.split works:

import re

s = """Paragraph 1
some text blah blah
blah blah
UNWANTED TEXT
some text
Paragraph END

UNWANTED TEXT

Paragraph 2
some text blah blah
blah blah
UNWANTED TEXT
Paragraph END"""
reg_para = re.compile(r'(Paragraph\s+\d+.+?END)', re.DOTALL)
paras = reg_para.split(s)
for para in paras:
    if reg_para.match(para):
        para = re.sub(r"UNWANTED TEXT", " ", para)
        #  in case you want replace more words:
        #  of course you can use list of keywords some loops
        para = re.sub(r"Another WORD", " ", para)
        print(para)
    else:
        print(para)

Output:

Paragraph 1
some text blah blah
blah blah
 
some text
Paragraph END


UNWANTED TEXT


Paragraph 2
some text blah blah
blah blah
 
Paragraph END