Python Regex to identify IPv4 address from string [duplicate]

Question

I am kindof stuck in extracting an IPv4 address from a String.

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My input string & constraints are as follows :

• IPv4 Range : 0.0.0.0 to 255.255.255.255
• IPv4 address may / may not be present in the string
  • Valid Examples : this is an ip & this is an ip 200.100.2.32
• String may start with IPv4 address
  • Valid Examples : 200.100.2.32 is an ip | Output : ['200.100.2.32']
  • Invalid Examples : 200.100.2.32is an ip | Output : []
• String may end with IPv4 address
  • Valid Examples : the ip is 200.100.2.32 | Output : ['200.100.2.32']
  • Invalid Examples : the ip is200.100.2.32 | Output : []
• String may contain an IPv4 address in the middle, and if it does - there will a space before and after the IPv4 address.
  • Valid Examples : the ip is 200.100.2.32 and it is ipv4 | Output : ['200.100.2.32']
  • Valid Examples : the ip is 200.100.2.32and it is ipv4 | Output : []
• Multiple IPs may be present in a single string
  • Valid Examples : 200.100.2.32 100.50.1.16 | Output : ['200.100.2.32', '100.50.1.16']
  • Invalid Examples : 200.100.2.32.100.50.1.16 | Output : []

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I am trying to build a regex for the above cases, they look fairly straightforward, and I am not able to incorporate all the regex checks.

I have been referring to the answers on these links : Link1, Link2, Link3

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Can someone help me in the right direction? To Summarize :

• IPv4 will have a space before it or starts at the begining of the string
• IPv4 will have a space after it or finishes at the end of the string
• IPv4 obeys the range : 0.0.0.0 to 255.255.255.255

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Code

def find_ip(str) :
    ip_pattern = re.compile('\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\s') # need to strengthen the regex here
    ip = re.findall(ip_pattern, str)
    return ip

Answer 1

The regex:

(?:^|\b(?<!\.))(?:1?\d\d?|2[0-4]\d|25[0-5])(?:\.(?:1?\d\d?|2[0-4]\d|25[0-5])){3}(?=$|[^\w.])

An example of matches.