Search patterns from the text file and if pattern missing place a value Null

问题

Esteemed colleagues, I have a raw data format as i detailed below where primarily it has to be three line and every line is starts with pattern dn: following ftpuser and description, whereas there are situations where the third line description is missing hence First two lines are intacted in this case. Now, I'm using a multiline regex to match all these patterns and using it to get the data from my data variable and this is passed to the regex(re.findall), Further, i have for looped the matchObj to get the values in a index form so i have can only the desired indexes from new_str List.

Below is the Data File :

dn: uid=ac002,ou=ftpusers,ou=applications,o=regg.com
ftpuser: Y
description: file transfer|12/31/2010|file transfer

dn: uid=ab02,ou=ftpusers,ou=applications,o=regg.com
ftpuser: disabled_5Mar07
description: Remedy Tkt 01239399 regg move

dn: uid=mela,ou=ftpusers,ou=applications,o=regg.com
ftpuser: Y
description: ROYALS|none|customer account

dn: uid=aa01,ou=ftpusers,ou=applications,o=regg.com
ftpuser: T

dn: uid=aa02,ou=ftpusers,ou=applications,o=regg.com
ftpuser: Y

dn: uid=aa03,ou=ftpusers,ou=applications,o=regg.com
ftpuser: Y

dn: uid=bb01,ou=ftpusers,ou=applications,o=regg.com
ftpuser: T

dn: uid=bb02,ou=ftpusers,ou=applications,o=regg.com
ftpuser: Y

dn: uid=bb03,ou=ftpusers,ou=applications,o=regg.com
ftpuser: Y

dn: uid=bb05,ou=ftpusers,ou=applications,o=regg.com
ftpuser: Y

dn: uid=ab01,ou=ftpusers,ou=applications,o=regg.com
ftpuser: Y
description:: VGVzdGluZyA=

dn: uid=tt@regg.com,ou=ftpusers,ou=applications,o=regg.com
ftpuser: T
description: REG-JP|7-31-05|REG-JP

Below is the code which i tried, but the problem here is as , this code only picks the data where it gets all three lines (dn:,ftpuser,description) and line where it has only two lines ((dn:,ftpuser) it fails to retrieve those hence i would like to know , how we can get those line also into the similar output making/appending Description: null wherever its missing

#!/usr/bin/python3
# ./dataparse.py
from __future__ import print_function
from signal import signal, SIGPIPE, SIG_DFL
signal(SIGPIPE,SIG_DFL)
import re
with open('test2', 'r') as f:
    for line in f:
        line = line.strip()
        data = f.read()
        regex = (r"dn:(.*?)\nftpuser: (.*)\ndescription:* (.*)")
        matchObj = re.findall(regex, data)
        for index in matchObj:
            #print(index)
            index_str = ' '.join(index)
            new_str = re.sub(r'[=,]', ' ', index_str)
            new_str = new_str.split()
            print("{0:<30}{1:<20}{2:<50}".format(new_str[1],new_str[8],new_str[9]))

Resulted output:

$ ./dataparse.py
ab02                          disabled_5Mar07     Remedy
mela                          Y                   ROYALS|none|customer
ab01                          Y                   VGVzdGluZyA
tt@regg.com                   T                   REG-JP|7-31-05|REG-JP

As a python beginner i would appreciate any help or suggestion.

回答1:

Simply make description optional in your regex pattern. Change it to:

r"dn:(.*?)\nftpuser: (.*)\n(?:description:* (.*))?"

来源：https://stackoverflow.com/questions/51106466/search-patterns-from-the-text-file-and-if-pattern-missing-place-a-value-null

标签

python-3.6