Replace multiple newlines with single newlines during reading file

Question

I have the next code which reads from multiple files, parses obtained lines and prints the result:

import os
import re

files=[]
pars=[]

for i in os.listdir('path_to_dir_with_files'):
    files.append(i)

for f in files:
    with open('path_to_dir_with_files'+str(f), 'r') as a:
       pars.append(re.sub('someword=|\,.*|\#.*','',a.read()))

for k in pars:
   print k

But I have problem with multiple new lines in output:

test1


test2

Instead of it I want to obtain the next result without empty lines in output:

 test1
 test2

and so on.

I tried playing with regexp:

pars.append(re.sub('someword=|\,.*|\#.*|^\n$','',a.read()))

But it doesn't work. Also I tried using strip() and rstrip() including replace. It also doesn't work.

Answer 1

You could use a second regex to replace multiple new lines with a single new line and use strip to get rid of the last new line.

import os
import re

files=[]
pars=[]

for i in os.listdir('path_to_dir_with_files'):
    files.append(i)

for f in files:
    with open('path_to_dir_with_files/'+str(f), 'r') as a:
        word = re.sub(r'someword=|\,.*|\#.*','', a.read())
        word = re.sub(r'\n+', '\n', word).strip()
        pars.append(word)

for k in pars:
   print k