is_valid_ip.php

<?php
// 6 kyu - IP Validation
// Write an algorithm that will identify valid IPv4 addresses in dot-decimal format. IPs should be considered valid if they consist of four octets, with values between 0..255 (included).
//
// Input to the function is guaranteed to be a single string.
//
// Examples
// // valid inputs:
// 1.2.3.4
// 123.45.67.89
//
// // invalid inputs:
// 1.2.3
// 1.2.3.4.5
// 123.456.78.90
// 123.045.067.089
// Note: leading zeros (e.g. 01.02.03.04) are considered not valid in this kata!

function isValidIP(string $str): bool {
  $arr = explode(".", $str);
  $valid_num = array_filter($arr, function($n) {
    return is_numeric($n) && intval($n) <= 255 && preg_match('/\s/', $n) === 0;
  });
  return count($valid_num) === 4 ? true : false;
}

// Alternative Solution:
// function isValidIP(string $str): bool
// {
//     return filter_var($str, FILTER_VALIDATE_IP);
// }

?>