Match IPv4 Address

Use regex to validate dotted-decimal IPv4 addresses.

regex validation ipv4

Write a function `match_ipv4(address: str) -> bool` that returns `True` if the given string is a valid IPv4 address in dotted-decimal notation, and `False` otherwise.

A valid IPv4 address consists of four decimal numbers separated by single dots. Each number must be an integer from 0 to 255 inclusive, with no leading zeros (except the number 0 itself). Leading or trailing whitespace should not be allowed. The entire string must exactly match the pattern — no extra characters.

For example:
- `"192.168.1.1"` is valid.
- `"255.255.255.255"` is valid.
- `"0.0.0.0"` is valid.
- `"01.2.3.4"` is invalid because of the leading zero.
- `"256.1.1.1"` is invalid because 256 is out of range.
- `"1.2.3"` is invalid because it has only three parts.
- `"1.2.3.4.5"` is invalid because it has five parts.
- `"1.2.3.4 "` is invalid because of trailing whitespace.

Implement the function using a single regular expression. You may use the `re` module.

Constraints

Input is a string of length between 0 and 50 characters. The function should return a boolean. The regex should be compiled with `re.fullmatch` or equivalently anchored with `^` and `$`.

Example

>>> match_ipv4("192.168.1.1")
True
>>> match_ipv4("256.1.1.1")
False
>>> match_ipv4("01.2.3.4")
False

8 points ~12 min

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Hints

Think about how to represent numbers 0-255 without leading zeros using a regex pattern.

Remember to anchor the pattern so it matches the entire string, not just a substring.

You can use `re.fullmatch` to require the whole string to match.

Consider separating the four octets with a literal dot in the pattern.

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