Python Regex pattern matching digits and words question?

Question

I'm having hard time creating a regex pattern and maybe you could help.

1.Target is to get only the result which is in BOLD and not the command with grep xxxx?

var = "grep " +net+ "/mnt/hgfs/IRR/fgen.txt"
f2pat = re.findall(r'^([\d]{1,3})\.(?:[\d]{1,3})\.(?:[\d]{1,3})\.(?:[\d]{1,3})/\d+',fgen)    
print ("FGEN Command: ",f2pat)

FGEN Command: grep 223.253.0.0/20 /mnt/hgfs/IRR/fgen.txt 223.253.0.0/20

Now I do have two addresses in the output 1 is from the command itself second is the result(bold) and just want to match the result.

2. Target is get the digits after the word member: AS xxxxx (BOLD)? /mnt/hgfs/IR/FILE/as4431-customers-sc:members: AS 28723 , AS3212

   fpas = re.findall(r'(^members: AS)(?:\\d{1,6})',xxx)

3. Target is to get/match the ip address(bold) after the work route:? RADB: route: 1.0.0.0/8

   radbpat = re.findall(r'(?<=RADB:)(\\S+ \\S+)(?<=route)(\\S+ \\S+)(?:[\\d]{1,3}).(?:[\\d]{1,3}).(?:[\\d]{1,3}).(?:[\\d]{1,3})/\\d+',who)

My regex patter doesn't work properly.

Thank you

Answer 1

For the first one, it appears that the subnet you want is located at the end of the string, so you can just capture exactly that:

text = 'grep 223.253.0.0/20 /mnt/hgfs/IRR/fgen.txt 223.253.0.0/20'
result = re.match('^.+\s([\d\.\/]+)$', text).group(1)
# result = '223.253.0.0/20'

---

For the second one, it looks like you just only want to capture the first instance of AS xxxxx , so you can do:

text = '/mnt/hgfs/IR/FILE/as4431-customers-sc:members: AS28723, AS3212'
result = re.match('^.+\b(AS\d+)\b.+$', text).group(1)
# result = 'AS28723'

---

For the third one, you can reuse the first solution:

text = 'RADB: route: 1.0.0.0/8'
result = re.match('^.+\s([\d\.\/]+)$', text).group(1)
# result = '1.0.0.0/8'