partial string comparision in php

i have stored two ip address values in two strings

a = '116.95.123.111'
b = '116.95.122.112'

i just want to compare the first two parts of ip address i.e 116.95 part in the two string开发者_开发百科s and as it is same in both the strings my comparison should return true. how to do this partial string comparison in PHP?

substr_compare is binary safe.

IP adresses can contain leading zeroes. When exploding, they can be compared to as integers, so that leading zeroes are ignored.

$a = "116.95.123.111";
$b = "116.095.123.111"   // same IP as $a, but with leading zero

The "clean" way would be by something like this...

$ip1 = explode(".", $a);
$ip2 = explode(".", $b);

if (($ip1[0] == $ip2[0]) && (ip1[1] == $ip2[1])) {
  // success. Do something
} else {
  // not valid
}

in this particular case (comparing ip addresses)

if((ip2long($a) >> 16) == (ip2long($b) >> 16)) echo "equal";