php实现快速对二维数组某一列进行组装的方法小

$user = array(
 '0'=> array('id'=>100,'username'=>'a1'),
 '1'=> array('id'=>101,'username'=>'a2'),
 '2'=> array('id'=>102,'username'=>'a3'),
 '3'=> array('id'=>103,'username'=>'a4'),
 '4'=> array('id'=>104,'username'=>'a5'),
)

$user = array(
 '0'=> array('id'=>100,'username'=>'a1'),
 '1'=> array('id'=>101,'username'=>'a2'),
 '2'=> array('id'=>102,'username'=>'a3'),
 '3'=> array('id'=>103,'username'=>'a4'),
 '4'=> array('id'=>104,'username'=>'a5'),
);
/
 @param array $array 数组
 @param string $k 要获取值的key
 @param array $rm 要去除的数据
 /
function array_get_v($array, $k, $rm)
{ 
 if (!trim($k)) return false;
 preg_match_all("/\"$k\":(\d+)/", json_encode($array), $res);
 $res = array_diff($res[1],$rm);
 return implode(',',$res);
}
print_r(array_get_v($user, 'id',array(101)));

$user = array(
'0' => array('id' => 100, 'username' => 'a1'),
'1' => array('id' => 101, 'username' => 'a2'),
'2' => array('id' => 102, 'username' => 'a3'),
'3' => array('id' => 103, 'username' => 'a4'),
'4' => array('id' => 104, 'username' => 'a5'),
);
array_walk($user, function($v, $k) use(&$ids){
 $ids[$k] = $v['id'];
});
echo implode(',', $ids);

<?php
function process($v){
 //如果要加限制条件，在这里加入即可
 if(isset($v['id']))
  return $v['id'];
}
$user = array(
 '0' => array('id' => 100, 'username' => 'a1'),
 '1' => array('id' => 101, 'username' => 'a2'),
 '2' => array('id' => 102, 'username' => 'a3'),
 '3' => array('id' => 103, 'username' => 'a4'),
 '4' => array('id' => 104, 'username' => 'a5'),
);
$aUser = array_map("process", $user);
echo implode(',', $aUser);