このような配列値を取得するにはどうすればよいでしょうか?

配列(100) {
[0] => 文字列(3) "1_1"
[2] => 文字列(3) "2_2"
[ 3] => 文字列(3) "3_1"
[4] => 文字列(3) "3_2"
.....
}
「3_」を入力すると
array(3) {
["0"] => string(1) "1"
["1"] => string(1) "2"
["2" ] => string(1) "3"
これが選択方法ですか?

ディスカッションへの返信(解決策)

$data =array("1_1","2_1","2_2","3_1","3_2","3_3");$need="3_";$ret = array_filter($data,function($item) use($need){	return strpos($item,$need) === 0;});var_dump($ret);

$d = array(  "1_1",  "2_1",  "2_2",  "3_1",  "3_2",  "3_3",);$in = '3_';$out = array_values(  array_map(function($s) use (&$in) {    return substr($s, strlen($in));  }, preg_grep("/$in/", $d)));print_r($out);

Array(    [0] => 1    [1] => 2    [2] => 3)

$data =array("1_1","2_1","2_2","3_1","3_2","3_3");$need="3_";$ret = array_filter($data,function($item) use($need){	return strpos($item,$need) === 0;});var_dump($ret);

ああ、後半だけ

$data =array("1_1","2_1 ","2_2"," 3_1 ","3_2","3_3");

$need="3_";


$ret =array();

foreach($data as $item){
if(strpos($item,$必要) === 0){
$ret[] = substr($item,strlen($need))
}
}

var_dump($ret);