求解数组序号及所在位置
$arr = array (
0 =>
array (
0 => 'su14031300617',
'po_num' => 'su14031300617',
),
1 =>
array (
0 => 'su14031300623',
'po_num' => 'su14031300623',
),
2 =>
array (
0 => 'su14031300626',
'po_num' => 'su14031300626',
),
3 =>
array (
0 => 'su14031300627',
'po_num' => 'su14031300627',
),
4 =>
array (
0 => 'su14031300616',
'po_num' => 'su14031300616',
),
5 =>
array (
0 => 'su14031300618',
'po_num' => 'su14031300618',
),
6 =>
array (
0 => 'su14031300622',
'po_num' => 'su14031300622',
),
7 =>
array (
0 => 'su14031300624',
'po_num' => 'su14031300624',
),
8 =>
array (
0 => 'su14031300625',
'po_num' => 'su14031300625',
),
)
假设su14031300617这项，所在数组的位置是8项中的第1项，表示为 1/8，通过序号可求得。请问怎么求解？
------解决方案--------------------
foreach($arr as $k=>$tmp) {
if('su14031300617' == $tmp[0]) {
return ($k+1) . '/' . count($arr);
}
}
return false;