关于php验证的函数问题，报错

$not_needed = ['verify', ];

foreach($post as $item => $value){
	if(!in_array($item, $not_needed)){
		$here[] = '`' . $item . '`="' . $value . '"';
	}
}

$here = implode(' and ', $here);
$sql = 'select * from table_name where ' . $here;

unset($arr['verify']);

$str = '`'.implode('`,`', array_keys('$arr')).'`'; 

function select($table,$arr){
unset($arr['verify']);
$str = '`'.implode('`,`', array_keys($arr)).'`';
foreach($arr as $val){
$val = "'".$val."'";
}
$arr = "'".implode("','", $arr)."'";
$sql = "select * from `{$table}`where {$str} = {$arr}";
print_r($sql);
// $query = mysql_query($sql);
// return $query;


}
打印出来的效果：

打印出来，select * from `admin_user`where `user`= ‘kopa’ and `password` = '3363064'

foreach($post as $item => $value){ if(!in_array($item, $not_needed)){ $here[] = '' . $item . '="' . $value . '"'; } }

$here = implode(' and ', $here); $sql = 'select * from table_name where ' . $here;

function select($table,$arr){
    foreach ($arr as $key => $value) {
    $here[] = '`'.$key.'`='.$value;
}
    $here = implode(' and ', $here);
    $sql = "select * from $table where ".$here;
    print_r($sql);
//验证码环节在提交的时候unset掉了 }