<form action="rensou.php" method="POST">
    <input name="name" type="text"><br>
    <input name="name2" type="text"><br>
    <input name="name3" type="text"><br>
    <input name="name4" type="text"><br>
    <input name="name5" type="text"><br>
    <input name="name6" type="text"><br>
    <input name="name7" type="text"><br>
    <input type="submit"><br>
</form>
<?php
$_POST = xss_d($_POST);
$array = [];
if(is_array($_POST)){
    foreach ($_POST as $key => $value) {
        if($value<>""){
            $array[$key] = $value;
        }
    }
}
?>
連想配列表示<br>
<textarea style="width: 500px;height: 500px;">
<?php
print_r (count($array)>0)?($array):["値無し"];
?>
</textarea>

<?php
function xss_d($val){
    if(is_array($val)){
        foreach ($val as $key => $value) {
            # code...
            $val[$key] = strip_tags($value);
            $val[$key] = htmlentities($val[$key],ENT_QUOTES);
        }
    }else{

        $val = strip_tags($val);
        $val = htmlentities($val,ENT_QUOTES);        
    }
    return $val;
}