数组操作-将下标变成从0开始的连续数字

array (size=3)
0 =>
array (size=2)
'channel' => int 0
'num' => int 170
13 =>
array (size=2)
'channel' => int 1
'num' => int 6
14 =>
array (size=2)
'channel' => int 2
'num' => int 2

foreach($arr as $value){
$new[] = $value;
}

array (size=3)
0 =>
array (size=2)
'channel' => int 0
'num' => int 170
1 =>
array (size=2)
'channel' => int 1
'num' => int 6
2 =>
array (size=2)
'channel' => int 2
'num' => int 2