<?php
$string1 = "one mice";
$string2 = "one .mice";
$string3 = "mice";
if (preg_match("/(?<![a-z] )\.?\bmice\b/i", $string1)) { echo "1"; } if (preg_match("/(?<![a-z] )\.?\bmice\b/i", $string2)) { echo "2"; } if (preg_match("/(?<![a-z] )\.?\bmice\b/i", $string3)) { echo "3"; }
PD9waHAKCiRzdHJpbmcxID0gIm9uZSBtaWNlIjsKJHN0cmluZzIgPSAib25lIC5taWNlIjsKJHN0cmluZzMgPSAibWljZSI7CgppZiAocHJlZ19tYXRjaCgiLyg/PCFbYS16XSApXC4/XGJtaWNlXGIvaSIsICRzdHJpbmcxKSkgeyBlY2hvICIxIjsgfQppZiAocHJlZ19tYXRjaCgiLyg/PCFbYS16XSApXC4/XGJtaWNlXGIvaSIsICRzdHJpbmcyKSkgeyBlY2hvICIyIjsgfQppZiAocHJlZ19tYXRjaCgiLyg/PCFbYS16XSApXC4/XGJtaWNlXGIvaSIsICRzdHJpbmczKSkgeyBlY2hvICIzIjsgfQo=