CODEWITHSUNDEEP
python-3.xregex
Akshay J
Akshay J

Reputation: 5468

Regex for multiple matches of IP addresses

I have a string:

unit 3 {
    arp-options {
        aging-timer 5;
    }
    family inet4 {
        address 2.33.1.2/255.255.255.0;
        address 2.33.2.2/255.255.255.0;
        address 2.33.3.2/255.255.255.0;
        address 2.33.4.2/255.255.255.0;
    }
}

I want to extract the IPV4 addresses ONLY under the family inet4 section. I can use the regex \d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3} for IP addresses but how to get all the IP addresses in one shot?

Upvotes: 0

Views: 306

Answers (3)

RavinderSingh13
RavinderSingh13

Reputation: 133730

With your shown samples, please try following.

##importing re library of python here.
import re
##Creating variable val which has OP's shown value here.
val="""unit 3 {
    arp-options {
        aging-timer 5;
    }
    family inet4 {
        address 2.33.1.2/255.255.255.0;
        address 2.33.2.2/255.255.255.0;
        address 2.33.3.2/255.255.255.0;
        address 2.33.4.2/255.255.255.0;
    }
}"""
##Creating val1 which will get all values from family inet4 to till last }.
val1=re.findall(r"(family inet4 {\n(?:.*;\n){1,}\s+})",val,re.MULTILINE)
##Creating regex2 here with .compile which will exactly match IP addresses which are just before / here.
regex2=re.compile(r"(\d{1,3}(?:\.\d{1,3}){3})/(\d{1,3}(?:\.\d{1,3}){3})")
##Using findall on val2 value to get all IP addresses here.
regex2.findall(str(val1))
[('2.33.1.2', '255.255.255.0'), ('2.33.2.2', '255.255.255.0'), ('2.33.3.2', '255.255.255.0'), ('2.33.4.2', '255.255.255.0')]

Upvotes: 1

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 627341

You can if you use PyPi regex module:

import regex

text = """unit 3 {
    arp-options {
        aging-timer 5;
    }
    family inet4 {
        address 2.33.1.2/255.255.255.0;
        address 2.33.2.2/255.255.255.0;
        address 2.33.3.2/255.255.255.0;
        address 2.33.4.2/255.255.255.0;
    }
}"""

matches = [x.captures(1) for x in regex.finditer(r"family inet4\s*{(?:\s*address\s+([\d./]+);)*\s*}", text)]
print([x for l in matches for x in l])
## => ['2.33.1.2/255.255.255.0', '2.33.2.2/255.255.255.0', '2.33.3.2/255.255.255.0', '2.33.4.2/255.255.255.0']

See an online Python demo.

The family inet4\s*{(?:\s*address\s+([\d./]+);)*\s*} regex matches

  • family inet4 - a string
  • \s* - zero or more whitespace
  • { - a { char
  • (?:\s*address\s+([\d./]+);)* - zero or more occurrences of
    • \s*address\s+ - zero or more whitespaces, address word, one or more whitespaces
    • ([\d./]+) - Group 1: one or more digits, ., or / chars
    • ; - a ; char
  • \s* - zero or more whitespaces
  • } - a } char.

With a standard re in Python, you can still use a single family inet4\s*{([^{}]*)} regex and some more post-processing to get the same:

import re
text = "STRING_HERE"
m = re.search(r"family inet4\s*{([^{}]*)}", text)
if m:
    res = [x.strip().split()[-1].strip(';') for x in m.group(1).strip().splitlines()]
    print(res)

See this Python demo. Here, family inet4\s*{([^{}]*)} matches family inet4, zero or more whitespaces, {, and then captures any zero or more chars into Group 1, and then matches a }.

Then, all whitespaces are stripped from the match, the match text is split into lines, and each line is processed with x.strip().split()[-1].strip(';'): 1) stipping whitespace first, then splitting with whitespace and getting the last item (the IP here), and then stipping the ; from the value.

Upvotes: 1

Tim Biegeleisen
Tim Biegeleisen

Reputation: 522571

I would extract the family inet4 section and then use re.findall:

inp = """unit 3 {
    arp-options {
        aging-timer 5;
    }
    family inet4 {
        address 2.33.1.2/255.255.255.0;
        address 2.33.2.2/255.255.255.0;
        address 2.33.3.2/255.255.255.0;
        address 2.33.4.2/255.255.255.0;
    }
}"""

inet = re.findall(r'\bfamily inet4 \{\s+(.*?)\s+\}', inp, flags=re.DOTALL)
ip_addresses = re.findall(r'\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b', inet[0])
print(ip_addresses)

This prints:

['2.33.1.2', '255.255.255.0', '2.33.2.2', '255.255.255.0',
 '2.33.3.2', '255.255.255.0', '2.33.4.2', '255.255.255.0']

Upvotes: 2

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