字符串截取,该怎么解决

字符串截取
bri=bridge0 if1=wan if2=lan if3=vlan mac=00:11:22:1d:2d:3d ip=192.168.100.1 netmask=255.255.255.0 arp=arp state=stop

bri=bridge1 if1=wan mac=00:01:2B:4C:6D:9F ip=192.168.1.125 netmask=255.255.255.0 state=stop

这是我保存的配置文件
但是 if打头的是多选的,个数是不固定的,最多8个,我想取出 if的值
也就是
bridge0 : wan lan vlan
bridge1 : wan
这条数据我转成数组是

PHP code

<!--Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->Array(    [0] =&gt; Array        (            [bri] =&gt; bridge0            [if1] =&gt; wan            [if2] =&gt; lan            [if3] =&gt; vlan            [mac] =&gt; 00:11:22:1d:2d:3d            [ip] =&gt; 192.168.100.1            [netmask] =&gt; 255.255.255.0            [arp] =&gt; arp            [state] =&gt; stop        )    [1] =&gt; Array        (            [bri] =&gt; bridge1            [if1] =&gt; wan            [mac] =&gt; 00:01:2B:4C:6D:9F            [ip] =&gt; 192.168.1.125            [netmask] =&gt; 255.255.255.0            [state] =&gt; stop        ))

请问有什么好的办法么,难道我真要
转成数组之后在根据键值判断

------解决方案--------------------

PHP code

$s = "bri=bridge0 if1=wan if2=lan if3=vlan mac=00:11:22:1d:2d:3d ip=192.168.100.1 netmask=255.255.255.0 arp=arp state=stop";parse_str(strtr($s, ' ', '&amp;'), $a);print_r($a);<br><font color="#e78608">------解决方案--------------------</font><br>不就是找哪个key是if开头的吗.<br><br>

PHP code

[User:root Time:17:19:16 Path:/home/liangdong/php]$ php preg.php bridge0: wan lan vlanbridge1: wan[User:root Time:17:19:16 Path:/home/liangdong/php]$ cat preg.php <?php $str = <<<EOFbri=bridge0 if1=wan if2=lan if3=vlan mac=00:11:22:1d:2d:3d ip=192.168.100.1 netmask=255.255.255.0 arp=arp state=stopbri=bridge1 if1=wan mac=00:01:2B:4C:6D:9F ip=192.168.1.125 netmask=255.255.255.0 state=stopEOF;$rows = explode(PHP_EOL, $str);foreach ($rows as $row) {        $cols = preg_split('/\s+/', $row);        $line = explode('=', $cols[0])[1] . ":";        foreach ($cols as $col) {                $fields = explode('=', $col);                if (strncmp($fields[0], "if", 2) === 0) {                        $line .= " " . $fields[1];                }        }        echo $line . PHP_EOL;}?><div class="clear">
                 
              
              
        
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